diff --git a/app/src/main/java/de/jeanlucmakiola/agendula/AgendulaApp.kt b/app/src/main/java/de/jeanlucmakiola/agendula/AgendulaApp.kt
index 1b8c87f..517bfc3 100644
--- a/app/src/main/java/de/jeanlucmakiola/agendula/AgendulaApp.kt
+++ b/app/src/main/java/de/jeanlucmakiola/agendula/AgendulaApp.kt
@@ -7,15 +7,16 @@ import dagger.hilt.InstallIn
 import dagger.hilt.android.EntryPointAccessors
 import dagger.hilt.android.HiltAndroidApp
 import dagger.hilt.components.SingletonComponent
+import de.jeanlucmakiola.agendula.data.di.ApplicationScope
 import de.jeanlucmakiola.agendula.data.reminders.ReminderScheduler
+import de.jeanlucmakiola.agendula.data.tasks.ProviderResolver
 import de.jeanlucmakiola.agendula.data.tasks.StartupGate
 import de.jeanlucmakiola.agendula.data.tasks.room.DatabaseCheckpoint
 import de.jeanlucmakiola.floret.crash.CrashConfig
 import de.jeanlucmakiola.floret.crash.CrashReporter
 import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.SupervisorJob
 import kotlinx.coroutines.launch
+import java.util.concurrent.atomic.AtomicBoolean
 
 /**
  * Application entry point. Registered as android:name=".AgendulaApp". Besides
@@ -43,14 +44,23 @@ class AgendulaApp : Application() {
         // Mirror the stored storage mode into ProviderResolver and import a
         // v0.3.x install's tasks, both before anything reads a store.
         val startupGate = entryPoint.startupGate()
+        val scope = entryPoint.applicationScope()
+        // An alarm is armed off whichever store was active when it was scheduled,
+        // so a switch has to rebuild the set. Armed only once startup's own
+        // null -> stored transition is past, which the launch sync below covers.
+        val started = AtomicBoolean(false)
+        entryPoint.providerResolver().onModeChanged {
+            if (started.get()) scope.launch { runCatching { scheduler.sync() } }
+        }
         startupGate.start()
         ProcessLifecycleOwner.get().lifecycle.addObserver(entryPoint.databaseCheckpoint())
-        CoroutineScope(SupervisorJob() + Dispatchers.Default).launch {
+        scope.launch {
             // Wait for the stored mode and the import to land first. Rescheduling
             // alarms against whichever store autoMode happens to pick would arm
             // them off the wrong one — or off an empty one, mid-import.
             runCatching {
                 startupGate.awaitReady()
+                started.set(true)
                 scheduler.sync()
             }
         }
@@ -61,6 +71,10 @@ class AgendulaApp : Application() {
     interface AppEntryPoint {
         fun reminderScheduler(): ReminderScheduler
         fun startupGate(): StartupGate
+        fun providerResolver(): ProviderResolver
+
+        @ApplicationScope
+        fun applicationScope(): CoroutineScope
         fun databaseCheckpoint(): DatabaseCheckpoint
     }
 }
diff --git a/app/src/main/java/de/jeanlucmakiola/agendula/data/export/ExportWriter.kt b/app/src/main/java/de/jeanlucmakiola/agendula/data/export/ExportWriter.kt
index 0376c58..03f43d5 100644
--- a/app/src/main/java/de/jeanlucmakiola/agendula/data/export/ExportWriter.kt
+++ b/app/src/main/java/de/jeanlucmakiola/agendula/data/export/ExportWriter.kt
@@ -17,8 +17,23 @@ import javax.inject.Singleton
 /** Where an export ended up, for the UI to report. */
 data class ExportResult(val fileCount: Int, val taskListNames: List<String>)
 
-/** The export could not be written. Carries a cause worth showing a user. */
-class ExportFailedException(message: String, cause: Throwable? = null) : IOException(message, cause)
+/**
+ * Why an export failed, as a value rather than a message: the UI ships in eleven
+ * locales, so the wording has to come from a string resource.
+ */
+enum class ExportFailure {
+    FOLDER_UNAVAILABLE,
+    FOLDER_NOT_WRITABLE,
+    CANNOT_CREATE_FILE,
+    LOST_ACCESS,
+    WRITE_FAILED,
+}
+
+/** The export could not be written. */
+class ExportFailedException(
+    val failure: ExportFailure,
+    cause: Throwable? = null,
+) : IOException(failure.name, cause)
 
 /**
  * Writes [ExportDocument]s to a user-chosen location through the Storage Access
@@ -44,22 +59,30 @@ class ExportWriter @Inject constructor(
     /**
      * Writes every document into [treeUri], a directory the user picked.
      *
-     * Overwrites same-named files rather than letting SAF append " (1)" — an
-     * export is a snapshot, and silently accumulating `Groceries-3 (4).ics` makes
-     * the folder useless as a backup.
+     * A same-named file is truncated and rewritten in place rather than deleted
+     * and recreated: SAF would otherwise append " (1)" and turn the folder into
+     * an unusable pile of snapshots, and a delete that is not followed by a
+     * successful create loses the previous export outright.
+     *
+     * The directory is listed once. `DocumentFile.findFile` queries the whole
+     * tree per call, so looking each name up in the loop is one full
+     * cross-process directory scan per list.
      */
     suspend fun writeToTree(treeUri: Uri, documents: List<ExportDocument>): ExportResult =
         withContext(io) {
-            val tree = DocumentFile.fromTreeUri(context, treeUri)
-                ?: throw ExportFailedException("Cannot open the chosen folder")
-            if (!tree.canWrite()) throw ExportFailedException("The chosen folder is not writable")
+            runCatching {
+                val tree = DocumentFile.fromTreeUri(context, treeUri)
+                    ?: throw ExportFailedException(ExportFailure.FOLDER_UNAVAILABLE)
+                if (!tree.canWrite()) throw ExportFailedException(ExportFailure.FOLDER_NOT_WRITABLE)
+                val existing = tree.listFiles().associateBy { it.name }
 
-            documents.forEach { document ->
-                tree.findFile(document.fileName)?.delete()
-                val file = tree.createFile(MIME_ICALENDAR, document.fileName)
-                    ?: throw ExportFailedException("Cannot create ${document.fileName}")
-                write(file.uri, document.content)
-            }
+                documents.forEach { document ->
+                    val file = existing[document.fileName]
+                        ?: tree.createFile(MIME_ICALENDAR, document.fileName)
+                        ?: throw ExportFailedException(ExportFailure.CANNOT_CREATE_FILE)
+                    write(file.uri, document.content)
+                }
+            }.getOrElse { throw asExportFailure(it) }
             ExportResult(documents.size, documents.map { it.fileName })
         }
 
@@ -80,7 +103,7 @@ class ExportWriter @Inject constructor(
                             zip.closeEntry()
                         }
                     }
-                } ?: throw ExportFailedException("Cannot write to the chosen file")
+                } ?: throw ExportFailedException(ExportFailure.WRITE_FAILED)
             }.getOrElse { throw asExportFailure(it) }
             ExportResult(documents.size, documents.map { it.fileName })
         }
@@ -90,7 +113,7 @@ class ExportWriter @Inject constructor(
             // "wt" truncates. Without it a shorter export leaves the tail of the
             // previous, longer one behind and produces a corrupt file.
             context.contentResolver.openOutputStream(target, "wt")?.use { it.write(bytes) }
-                ?: throw ExportFailedException("Cannot write to the chosen file")
+                ?: throw ExportFailedException(ExportFailure.WRITE_FAILED)
         }.getOrElse { throw asExportFailure(it) }
     }
 
@@ -98,8 +121,8 @@ class ExportWriter @Inject constructor(
         is ExportFailedException -> cause
         // A SAF grant can be revoked between the picker and the write (the volume
         // was unmounted, the provider's process died, the user cleared the grant).
-        is SecurityException -> ExportFailedException("Lost access to the chosen location", cause)
-        is IOException -> ExportFailedException(cause.message ?: "Could not write the export", cause)
+        is SecurityException -> ExportFailedException(ExportFailure.LOST_ACCESS, cause)
+        is IOException -> ExportFailedException(ExportFailure.WRITE_FAILED, cause)
         else -> cause
     }
 
diff --git a/app/src/main/java/de/jeanlucmakiola/agendula/data/reminders/ReminderScheduler.kt b/app/src/main/java/de/jeanlucmakiola/agendula/data/reminders/ReminderScheduler.kt
index 089ee9d..58467e0 100644
--- a/app/src/main/java/de/jeanlucmakiola/agendula/data/reminders/ReminderScheduler.kt
+++ b/app/src/main/java/de/jeanlucmakiola/agendula/data/reminders/ReminderScheduler.kt
@@ -12,6 +12,8 @@ import de.jeanlucmakiola.agendula.data.tasks.TaskQuery
 import de.jeanlucmakiola.agendula.data.tasks.TasksDataSource
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
 import kotlinx.coroutines.withContext
 import javax.inject.Inject
 import javax.inject.Singleton
@@ -20,8 +22,8 @@ import javax.inject.Singleton
  * The self-scheduled due-reminder engine. Nothing else delivers task reminders —
  * not the platform, not a tasks provider — so Agendula reads upcoming due tasks
  * and arms one exact [AlarmManager] alarm each, within a rolling window. Re-run
- * on app start, on boot, and on an external provider change; it diffs against
- * [ScheduledReminderStore] so only changed alarms move.
+ * on app start, on boot, on a store switch, and on an external provider change;
+ * it diffs against [ScheduledReminderStore] so only changed alarms move.
  */
 @Singleton
 class ReminderScheduler @Inject constructor(
@@ -32,19 +34,32 @@ class ReminderScheduler @Inject constructor(
     private val providerResolver: ProviderResolver,
     @IoDispatcher private val io: CoroutineDispatcher,
 ) {
-    suspend fun sync() = withContext(io) {
+    private val syncLock = Mutex()
+
+    /**
+     * Diff the armed alarms against the store and move only what changed.
+     *
+     * Serialised: the diff is a read-modify-write over [ScheduledReminderStore],
+     * and callers overlap (a store switch fires this while the launch sync may
+     * still be running). Two interleaved runs would each write their own set as
+     * the whole truth, leaving the other's alarms armed but unrecorded — never
+     * cancelled, and firing against the wrong store's task ids.
+     */
+    suspend fun sync() = withContext(io) { syncLock.withLock { syncLocked() } }
+
+    private suspend fun syncLocked() {
         val settings = settingsPrefs.settings.first()
         // Gate on whether the store is readable, not on whether a provider
         // resolves: our own store deliberately resolves to no provider, so the
         // latter clears every reminder in the default mode.
         if (!settings.remindersEnabled || !providerResolver.canReadStore()) {
             clearAll()
-            return@withContext
+            return
         }
         val now = System.currentTimeMillis()
         val horizon = now + WINDOW_MS
         val tasks = runCatching { dataSource.tasks(TaskQuery(includeCompleted = false)) }
-            .getOrElse { return@withContext }
+            .getOrElse { return }
 
         // One reminder per *occurrence*: a recurring series yields a row per
         // occurrence, all sharing a taskId, so this is a Set rather than a
diff --git a/app/src/main/java/de/jeanlucmakiola/agendula/data/tasks/ProviderEnvironment.kt b/app/src/main/java/de/jeanlucmakiola/agendula/data/tasks/ProviderEnvironment.kt
index 4cfca57..e60193f 100644
--- a/app/src/main/java/de/jeanlucmakiola/agendula/data/tasks/ProviderEnvironment.kt
+++ b/app/src/main/java/de/jeanlucmakiola/agendula/data/tasks/ProviderEnvironment.kt
@@ -23,6 +23,9 @@ interface ProviderEnvironment {
 
     /** Whether this app currently holds [permission]. */
     fun isGranted(permission: String): Boolean
+
+    /** [packageName]'s own app name, or null when it cannot be read. */
+    fun appLabel(packageName: String): String?
 }
 
 @Singleton
@@ -35,4 +38,9 @@ class AndroidProviderEnvironment @Inject constructor(
 
     override fun isGranted(permission: String): Boolean =
         ContextCompat.checkSelfPermission(context, permission) == PackageManager.PERMISSION_GRANTED
+
+    override fun appLabel(packageName: String): String? = runCatching {
+        val pm = context.packageManager
+        pm.getApplicationLabel(pm.getApplicationInfo(packageName, 0)).toString()
+    }.getOrNull()
 }
diff --git a/app/src/main/java/de/jeanlucmakiola/agendula/ui/RootScreen.kt b/app/src/main/java/de/jeanlucmakiola/agendula/ui/RootScreen.kt
index fc41b08..3154095 100644
--- a/app/src/main/java/de/jeanlucmakiola/agendula/ui/RootScreen.kt
+++ b/app/src/main/java/de/jeanlucmakiola/agendula/ui/RootScreen.kt
@@ -10,19 +10,17 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.material3.Button
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.unit.dp
 import androidx.hilt.navigation.compose.hiltViewModel
-import androidx.lifecycle.Lifecycle
-import androidx.lifecycle.LifecycleEventObserver
-import androidx.lifecycle.compose.LocalLifecycleOwner
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import de.jeanlucmakiola.agendula.R
+import de.jeanlucmakiola.agendula.ui.common.OnResume
 import de.jeanlucmakiola.agendula.data.tasks.ProviderStatus
 import de.jeanlucmakiola.agendula.ui.navigation.AgendulaNavHost
 import de.jeanlucmakiola.agendula.ui.permission.PermissionViewModel
@@ -46,20 +44,20 @@ fun RootScreen(
     // Re-check on every resume, not just after the in-app request: the user may
     // have granted the permission (or installed a provider) in system Settings and
     // come back, and otherwise the gate would hold until the process restarts.
-    val lifecycleOwner = LocalLifecycleOwner.current
-    DisposableEffect(lifecycleOwner) {
-        val observer = LifecycleEventObserver { _, event ->
-            if (event == Lifecycle.Event.ON_RESUME) permissionViewModel.refresh()
-        }
-        lifecycleOwner.lifecycle.addObserver(observer)
-        onDispose { lifecycleOwner.lifecycle.removeObserver(observer) }
-    }
+    OnResume { permissionViewModel.refresh() }
+
+    // Neither gate can show in OWN mode (that store is always READY), so the way
+    // out of one is always our own store. Without it a user whose provider app
+    // went away is held on this screen with Settings behind it.
+    val fallback = stringResource(R.string.onboarding_use_own_store)
 
     when (permission.status) {
         ProviderStatus.NO_PROVIDER -> Gate(
             modifier = modifier,
             title = stringResource(R.string.onboarding_no_provider_title),
             body = stringResource(R.string.onboarding_no_provider_body),
+            secondaryAction = fallback,
+            onSecondaryAction = permissionViewModel::useOwnStore,
         )
         ProviderStatus.NEEDS_PERMISSION -> Gate(
             modifier = modifier,
@@ -67,6 +65,8 @@ fun RootScreen(
             body = stringResource(R.string.onboarding_permission_body),
             action = stringResource(R.string.onboarding_permission_button),
             onAction = { launcher.launch(permission.permissionsToRequest.toTypedArray()) },
+            secondaryAction = fallback,
+            onSecondaryAction = permissionViewModel::useOwnStore,
         )
         ProviderStatus.READY -> ReadyGate(modifier = modifier)
     }
@@ -103,6 +103,8 @@ private fun Gate(
     modifier: Modifier = Modifier,
     action: String? = null,
     onAction: () -> Unit = {},
+    secondaryAction: String? = null,
+    onSecondaryAction: () -> Unit = {},
 ) {
     Column(
         modifier = modifier.fillMaxSize().padding(24.dp),
@@ -112,5 +114,6 @@ private fun Gate(
         Text(title, style = MaterialTheme.typography.headlineSmall)
         Text(body, style = MaterialTheme.typography.bodyMedium)
         if (action != null) Button(onClick = onAction) { Text(action) }
+        if (secondaryAction != null) TextButton(onClick = onSecondaryAction) { Text(secondaryAction) }
     }
 }
diff --git a/app/src/main/java/de/jeanlucmakiola/agendula/ui/common/OnResume.kt b/app/src/main/java/de/jeanlucmakiola/agendula/ui/common/OnResume.kt
new file mode 100644
index 0000000..b29f473
--- /dev/null
+++ b/app/src/main/java/de/jeanlucmakiola/agendula/ui/common/OnResume.kt
@@ -0,0 +1,29 @@
+package de.jeanlucmakiola.agendula.ui.common
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.rememberUpdatedState
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.LifecycleEventObserver
+import androidx.lifecycle.compose.LocalLifecycleOwner
+
+/**
+ * Runs [block] on every `ON_RESUME`.
+ *
+ * For state the app cannot observe because it is granted, revoked or installed
+ * outside it — a runtime permission, an exact-alarm allowance, a provider app —
+ * which otherwise stays stale until the process restarts.
+ */
+@Composable
+fun OnResume(block: () -> Unit) {
+    val current by rememberUpdatedState(block)
+    val lifecycle = LocalLifecycleOwner.current.lifecycle
+    DisposableEffect(lifecycle) {
+        val observer = LifecycleEventObserver { _, event ->
+            if (event == Lifecycle.Event.ON_RESUME) current()
+        }
+        lifecycle.addObserver(observer)
+        onDispose { lifecycle.removeObserver(observer) }
+    }
+}
diff --git a/app/src/main/java/de/jeanlucmakiola/agendula/ui/export/ExportScreen.kt b/app/src/main/java/de/jeanlucmakiola/agendula/ui/export/ExportScreen.kt
new file mode 100644
index 0000000..c9ae0f1
--- /dev/null
+++ b/app/src/main/java/de/jeanlucmakiola/agendula/ui/export/ExportScreen.kt
@@ -0,0 +1,182 @@
+package de.jeanlucmakiola.agendula.ui.export
+
+import androidx.activity.compose.rememberLauncherForActivityResult
+import androidx.activity.result.contract.ActivityResultContracts
+import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.rounded.Circle
+import androidx.compose.material.icons.rounded.Folder
+import androidx.compose.material.icons.rounded.FolderZip
+import androidx.compose.material3.Button
+import androidx.compose.material3.Checkbox
+import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedButton
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.res.pluralStringResource
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import de.jeanlucmakiola.agendula.R
+import de.jeanlucmakiola.agendula.data.export.ExportFailure
+import de.jeanlucmakiola.floret.components.CollapsingScaffold
+import de.jeanlucmakiola.floret.components.GroupedRow
+import de.jeanlucmakiola.floret.components.Position
+import de.jeanlucmakiola.floret.components.pastelize
+import de.jeanlucmakiola.floret.components.positionOf
+
+private const val ZIP_MIME = "application/zip"
+private const val ZIP_NAME = "agendula-tasks.zip"
+
+/**
+ * Export the task lists as iCalendar. Which lists go out is a per-list tick; the
+ * destination is a folder or a single zip, both picked through SAF so the app
+ * needs no storage permission.
+ */
+@Composable
+fun ExportScreen(
+    onBack: () -> Unit,
+    modifier: Modifier = Modifier,
+    viewModel: ExportViewModel = hiltViewModel(),
+) {
+    val state by viewModel.state.collectAsStateWithLifecycle()
+    val dark = isSystemInDarkTheme()
+
+    val folderLauncher = rememberLauncherForActivityResult(
+        contract = ActivityResultContracts.OpenDocumentTree(),
+    ) { uri -> uri?.let(viewModel::exportToFolder) }
+    val zipLauncher = rememberLauncherForActivityResult(
+        contract = ActivityResultContracts.CreateDocument(ZIP_MIME),
+    ) { uri -> uri?.let(viewModel::exportToZip) }
+
+    val canExport = !state.running && state.selectedCount > 0
+
+    CollapsingScaffold(
+        title = stringResource(R.string.settings_export),
+        onBack = onBack,
+        modifier = modifier,
+    ) {
+        Text(
+            text = stringResource(R.string.export_hint),
+            style = MaterialTheme.typography.bodyMedium,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+            modifier = Modifier.padding(horizontal = 16.dp, vertical = 4.dp),
+        )
+        Spacer(Modifier.height(16.dp))
+
+        if (state.lists.isEmpty()) {
+            GroupedRow(
+                title = stringResource(R.string.export_no_lists),
+                position = Position.Alone,
+                dimmed = true,
+            )
+        } else {
+            state.lists.forEachIndexed { index, list ->
+                val selected = state.isSelected(list.id)
+                GroupedRow(
+                    title = list.name,
+                    // The account only says something when it isn't the device itself.
+                    summary = list.accountName.takeIf { !list.isLocal },
+                    position = positionOf(index, state.lists.size),
+                    leading = {
+                        Icon(Icons.Rounded.Circle, contentDescription = null, tint = pastelize(list.color, dark))
+                    },
+                    trailing = {
+                        Checkbox(checked = selected, onCheckedChange = { viewModel.toggle(list.id) })
+                    },
+                    onClick = { viewModel.toggle(list.id) },
+                )
+            }
+        }
+
+        Spacer(Modifier.height(24.dp))
+        Column(
+            modifier = Modifier.fillMaxWidth().padding(horizontal = 16.dp),
+            verticalArrangement = Arrangement.spacedBy(8.dp),
+        ) {
+            Button(
+                onClick = { folderLauncher.launch(null) },
+                enabled = canExport,
+                modifier = Modifier.fillMaxWidth(),
+            ) {
+                Icon(Icons.Rounded.Folder, contentDescription = null, modifier = Modifier.size(18.dp))
+                Spacer(Modifier.size(8.dp))
+                Text(stringResource(R.string.export_to_folder))
+            }
+            OutlinedButton(
+                onClick = { zipLauncher.launch(ZIP_NAME) },
+                enabled = canExport,
+                modifier = Modifier.fillMaxWidth(),
+            ) {
+                Icon(Icons.Rounded.FolderZip, contentDescription = null, modifier = Modifier.size(18.dp))
+                Spacer(Modifier.size(8.dp))
+                Text(stringResource(R.string.export_to_zip))
+            }
+        }
+
+        Spacer(Modifier.height(16.dp))
+        ExportStatus(state = state)
+        Spacer(Modifier.height(24.dp))
+    }
+}
+
+/** The running spinner, then whatever the last export ended as — it stays put. */
+@Composable
+private fun ExportStatus(state: ExportUiState) {
+    val outcome = state.outcome
+    when {
+        state.running -> Row(
+            modifier = Modifier.fillMaxWidth().padding(horizontal = 16.dp),
+            verticalAlignment = Alignment.CenterVertically,
+            horizontalArrangement = Arrangement.spacedBy(12.dp),
+        ) {
+            CircularProgressIndicator(Modifier.size(18.dp))
+            Text(
+                text = stringResource(R.string.export_running),
+                style = MaterialTheme.typography.bodyMedium,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+            )
+        }
+        outcome is ExportOutcome.Success -> StatusText(
+            text = pluralStringResource(R.plurals.export_done, outcome.fileCount, outcome.fileCount),
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+        )
+        outcome is ExportOutcome.Failure -> StatusText(
+            text = stringResource(failureMessage(outcome.reason)),
+            color = MaterialTheme.colorScheme.error,
+        )
+    }
+}
+
+private fun failureMessage(reason: ExportFailure): Int = when (reason) {
+    ExportFailure.FOLDER_UNAVAILABLE -> R.string.export_failed_folder
+    ExportFailure.FOLDER_NOT_WRITABLE -> R.string.export_failed_read_only
+    ExportFailure.CANNOT_CREATE_FILE -> R.string.export_failed_create
+    ExportFailure.LOST_ACCESS -> R.string.export_failed_access
+    ExportFailure.WRITE_FAILED -> R.string.export_failed
+}
+
+@Composable
+private fun StatusText(text: String, color: Color) {
+    Text(
+        text = text,
+        style = MaterialTheme.typography.bodyMedium,
+        color = color,
+        modifier = Modifier.fillMaxWidth().padding(horizontal = 16.dp),
+    )
+}
diff --git a/app/src/main/java/de/jeanlucmakiola/agendula/ui/export/ExportViewModel.kt b/app/src/main/java/de/jeanlucmakiola/agendula/ui/export/ExportViewModel.kt
new file mode 100644
index 0000000..f091b9c
--- /dev/null
+++ b/app/src/main/java/de/jeanlucmakiola/agendula/ui/export/ExportViewModel.kt
@@ -0,0 +1,122 @@
+package de.jeanlucmakiola.agendula.ui.export
+
+import android.net.Uri
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import dagger.hilt.android.lifecycle.HiltViewModel
+import de.jeanlucmakiola.agendula.data.export.ExportFailedException
+import de.jeanlucmakiola.agendula.data.export.ExportFailure
+import de.jeanlucmakiola.agendula.data.export.ExportResult
+import de.jeanlucmakiola.agendula.data.export.ExportWriter
+import de.jeanlucmakiola.agendula.data.export.TaskExporter
+import de.jeanlucmakiola.agendula.data.tasks.ProviderResolver
+import de.jeanlucmakiola.agendula.data.tasks.TasksRepository
+import de.jeanlucmakiola.agendula.data.tasks.recoveringFromProviderFailure
+import de.jeanlucmakiola.agendula.domain.TaskList
+import de.jeanlucmakiola.agendula.domain.export.ExportDocument
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.flow.update
+import kotlinx.coroutines.launch
+import javax.inject.Inject
+import kotlin.coroutines.cancellation.CancellationException
+
+/** How the last export ended, kept on screen rather than flashed past. */
+sealed interface ExportOutcome {
+    data class Success(val fileCount: Int) : ExportOutcome
+    data class Failure(val reason: ExportFailure) : ExportOutcome
+}
+
+data class ExportUiState(
+    val lists: List<TaskList> = emptyList(),
+    /** Lists the user has ticked *off*; everything else is included. */
+    val excluded: Set<Long> = emptySet(),
+    val running: Boolean = false,
+    val outcome: ExportOutcome? = null,
+) {
+    fun isSelected(listId: Long): Boolean = listId !in excluded
+
+    val selectedCount: Int get() = lists.count { isSelected(it.id) }
+}
+
+/**
+ * Drives the export screen. Holds the selection as an exclusion set so a list
+ * that appears while the screen is open is exported too — the natural reading of
+ * "everything, minus what I unticked".
+ */
+@HiltViewModel
+class ExportViewModel @Inject constructor(
+    repository: TasksRepository,
+    resolver: ProviderResolver,
+    private val exporter: TaskExporter,
+    private val writer: ExportWriter,
+) : ViewModel() {
+
+    private val excluded = MutableStateFlow(emptySet<Long>())
+    private val running = MutableStateFlow(false)
+    private val outcome = MutableStateFlow<ExportOutcome?>(null)
+
+    private var exportJob: Job? = null
+
+    // List ids are per-store, and Settings can switch stores with this ViewModel
+    // still alive — so the selection, the receipt and a write already addressing
+    // the old store's lists all go with it.
+    private val modeHandle = resolver.onModeChanged {
+        exportJob?.cancel()
+        excluded.value = emptySet()
+        outcome.value = null
+    }
+
+    override fun onCleared() {
+        modeHandle.close()
+    }
+
+    val state: StateFlow<ExportUiState> =
+        combine(
+            repository.taskLists().recoveringFromProviderFailure { emptyList() },
+            excluded,
+            running,
+            outcome,
+        ) { lists, excluded, running, outcome ->
+            ExportUiState(lists, excluded, running, outcome)
+        }.stateIn(viewModelScope, SharingStarted.WhileSubscribed(5_000), ExportUiState())
+
+    fun toggle(listId: Long) = excluded.update { current ->
+        if (listId in current) current - listId else current + listId
+    }
+
+    /** Writes one `.ics` per list into a folder the user picked through SAF. */
+    fun exportToFolder(tree: Uri) = export { documents -> writer.writeToTree(tree, documents) }
+
+    /** Writes every list into a single zip the user named through SAF. */
+    fun exportToZip(target: Uri) = export { documents -> writer.writeZip(target, documents) }
+
+    private fun export(write: suspend (List<ExportDocument>) -> ExportResult) {
+        if (running.value) return
+        running.value = true
+        outcome.value = null
+        exportJob = viewModelScope.launch {
+            // Null means "every list" to the exporter, and is what an untouched
+            // screen should send: the flow may not have emitted a list yet.
+            val selection = excluded.value.takeIf { it.isNotEmpty() }
+                ?.let { skipped -> state.value.lists.map { it.id }.toSet() - skipped }
+            try {
+                val result = write(exporter.export(selection))
+                outcome.value = ExportOutcome.Success(result.fileCount)
+            } catch (cancelled: CancellationException) {
+                // Leaving the screen mid-write is not a failed export.
+                throw cancelled
+            } catch (error: Exception) {
+                outcome.value = ExportOutcome.Failure(
+                    (error as? ExportFailedException)?.failure ?: ExportFailure.WRITE_FAILED,
+                )
+            } finally {
+                running.value = false
+            }
+        }
+    }
+}
diff --git a/app/src/main/java/de/jeanlucmakiola/agendula/ui/permission/PermissionViewModel.kt b/app/src/main/java/de/jeanlucmakiola/agendula/ui/permission/PermissionViewModel.kt
index 4cdd0cf..5c1e89c 100644
--- a/app/src/main/java/de/jeanlucmakiola/agendula/ui/permission/PermissionViewModel.kt
+++ b/app/src/main/java/de/jeanlucmakiola/agendula/ui/permission/PermissionViewModel.kt
@@ -1,13 +1,25 @@
 package de.jeanlucmakiola.agendula.ui.permission
 
 import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
 import dagger.hilt.android.lifecycle.HiltViewModel
+import de.jeanlucmakiola.agendula.data.prefs.SettingsPrefs
 import de.jeanlucmakiola.agendula.data.tasks.ProviderResolver
 import de.jeanlucmakiola.agendula.data.tasks.ProviderStatus
+import de.jeanlucmakiola.agendula.data.tasks.StorageMode
 import de.jeanlucmakiola.agendula.data.tasks.TasksRepository
+import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.channels.awaitClose
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.buffer
 import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
-import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.callbackFlow
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.flow.update
+import kotlinx.coroutines.launch
 import javax.inject.Inject
 
 data class PermissionUiState(
@@ -21,25 +33,48 @@ data class PermissionUiState(
  * The Composable owns the actual permission-launcher and store intents; this VM
  * supplies the [status] and the exact permission strings to ask for.
  *
- * In the default Local mode this gate never appears at all — Agendula's own
- * provider ships in the APK and is reached same-uid, so there is nothing to
- * install and nothing to grant. It exists for External mode.
+ * In the default Own mode this gate never appears at all — the store is our own
+ * Room database, so there is nothing to install and nothing to grant. It exists
+ * for External mode, which also makes it the only screen an External user can
+ * reach once their provider app stops answering: hence [useOwnStore].
  */
 @HiltViewModel
 class PermissionViewModel @Inject constructor(
     private val repository: TasksRepository,
     private val providerResolver: ProviderResolver,
+    private val prefs: SettingsPrefs,
 ) : ViewModel() {
 
-    private val _state = MutableStateFlow(PermissionUiState())
-    val state: StateFlow<PermissionUiState> = _state.asStateFlow()
+    private val refreshes = MutableStateFlow(0)
 
-    init { refresh() }
+    // Re-evaluated when the *resolver's* mode lands, not when the preference is
+    // written: anything read in between still answers for the store we just left.
+    // Conflated, as everywhere else this signal is bridged: only the latest mode
+    // matters, and a full buffer drops it rather than the ones it supersedes.
+    private val modeChanges: Flow<Unit> = callbackFlow {
+        trySend(Unit)
+        val handle = providerResolver.onModeChanged { trySend(Unit) }
+        awaitClose { handle.close() }
+    }.buffer(Channel.CONFLATED)
+
+    val state: StateFlow<PermissionUiState> =
+        combine(refreshes, modeChanges) { _, _ -> currentState() }
+            .stateIn(viewModelScope, SharingStarted.WhileSubscribed(5_000), currentState())
 
     /** Re-read provider + permission state (call after returning from a request). */
-    fun refresh() {
+    fun refresh() = refreshes.update { it + 1 }
+
+    /**
+     * Leave a store this device can no longer read. The provider app can be
+     * uninstalled, or its permission revoked, after External was chosen — and the
+     * gate is then the only screen reachable, Settings included. Our own store
+     * always reads, so it is the way out.
+     */
+    fun useOwnStore() = viewModelScope.launch { prefs.setStorageMode(StorageMode.OWN) }
+
+    private fun currentState(): PermissionUiState {
         val provider = providerResolver.resolve()
-        _state.value = PermissionUiState(
+        return PermissionUiState(
             status = repository.providerStatus(),
             // Null in OWN mode, where there is no provider and nothing to grant.
             permissionsToRequest = provider
diff --git a/app/src/main/java/de/jeanlucmakiola/agendula/ui/settings/SettingsScreen.kt b/app/src/main/java/de/jeanlucmakiola/agendula/ui/settings/SettingsScreen.kt
index 712a61d..5c6da54 100644
--- a/app/src/main/java/de/jeanlucmakiola/agendula/ui/settings/SettingsScreen.kt
+++ b/app/src/main/java/de/jeanlucmakiola/agendula/ui/settings/SettingsScreen.kt
@@ -49,6 +49,7 @@ import androidx.compose.material.icons.rounded.AccountTree
 import androidx.compose.material.icons.rounded.Circle
 import androidx.compose.material.icons.rounded.Flag
 import androidx.compose.material.icons.rounded.Percent
+import androidx.compose.material.icons.rounded.Storage
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
@@ -56,7 +57,6 @@ import androidx.compose.material3.Surface
 import androidx.compose.material3.Switch
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
@@ -75,13 +75,11 @@ import androidx.compose.ui.unit.dp
 import androidx.core.content.ContextCompat
 import androidx.core.net.toUri
 import androidx.hilt.navigation.compose.hiltViewModel
-import androidx.lifecycle.Lifecycle
-import androidx.lifecycle.LifecycleEventObserver
-import androidx.lifecycle.compose.LocalLifecycleOwner
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import de.jeanlucmakiola.agendula.R
 import de.jeanlucmakiola.agendula.data.prefs.ThemeMode
 import de.jeanlucmakiola.agendula.domain.TaskFormField
+import de.jeanlucmakiola.agendula.ui.export.ExportScreen
 import de.jeanlucmakiola.floret.components.AboutCard
 import de.jeanlucmakiola.floret.components.AboutLink
 import de.jeanlucmakiola.floret.components.CollapsingScaffold
@@ -96,10 +94,22 @@ import de.jeanlucmakiola.floret.locale.AppLanguage
 import de.jeanlucmakiola.floret.identity.expandEnter
 import de.jeanlucmakiola.floret.reminders.ReminderOverride
 import de.jeanlucmakiola.floret.reminders.reminderOverrideFor
+import de.jeanlucmakiola.agendula.ui.common.OnResume
 import de.jeanlucmakiola.agendula.ui.common.reminderLeadTimeLabel
 
 /** The settings sub-screens reached from the hub's category rows. */
-private enum class SettingsSection { Appearance, TaskForm, Reminders }
+private enum class SettingsSection {
+    Appearance,
+    TaskForm,
+    Reminders,
+    Storage,
+    Export,
+    ;
+
+    /** Where back goes: Export is opened from Storage, not from the hub. */
+    val parent: SettingsSection?
+        get() = if (this == Export) Storage else null
+}
 
 /**
  * Token-based accent for a leading icon chip (container / on-container pair),
@@ -125,7 +135,7 @@ fun SettingsScreen(
 
     // Inside a sub-screen, system back (button or gesture) returns to the hub
     // rather than popping the whole Settings destination to the lists overview.
-    BackHandler(enabled = section != null) { section = null }
+    BackHandler(enabled = section != null) { section = section?.parent }
 
     Box(
         modifier = modifier
@@ -143,6 +153,19 @@ fun SettingsScreen(
         SlideInSection(visible = section == SettingsSection.Reminders) {
             RemindersScreen(state = state, viewModel = viewModel, onBack = { section = null })
         }
+        // Storage stays composed under Export, so the deeper screen slides over it.
+        val storageOpen = section == SettingsSection.Storage ||
+            section?.parent == SettingsSection.Storage
+        SlideInSection(visible = storageOpen) {
+            StorageScreen(
+                viewModel = viewModel,
+                onOpenExport = { section = SettingsSection.Export },
+                onBack = { section = null },
+            )
+        }
+        SlideInSection(visible = section == SettingsSection.Export) {
+            ExportScreen(onBack = { section = SettingsSection.Storage })
+        }
     }
 }
 
@@ -212,6 +235,13 @@ private fun SettingsHub(
             leading = { CategoryIcon(Icons.Default.Notifications, ChipAccent.Primary) },
             onClick = { onOpenSection(SettingsSection.Reminders) },
         )
+        GroupedRow(
+            title = stringResource(R.string.settings_section_storage),
+            summary = stringResource(R.string.settings_storage_subtitle),
+            position = Position.Middle,
+            leading = { CategoryIcon(Icons.Rounded.Storage, ChipAccent.Neutral) },
+            onClick = { onOpenSection(SettingsSection.Storage) },
+        )
         LanguageRow(position = Position.Middle)
         ReportProblemRow(position = Position.Bottom)
 
@@ -670,15 +700,10 @@ private fun rememberExactAlarmAllowed(context: Context): Boolean {
                 context.getSystemService(AlarmManager::class.java).canScheduleExactAlarms(),
         )
     }
-    val lifecycle = LocalLifecycleOwner.current.lifecycle
-    DisposableEffect(lifecycle) {
-        val obs = LifecycleEventObserver { _, event ->
-            if (event == Lifecycle.Event.ON_RESUME && Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {
-                allowed = context.getSystemService(AlarmManager::class.java).canScheduleExactAlarms()
-            }
+    OnResume {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {
+            allowed = context.getSystemService(AlarmManager::class.java).canScheduleExactAlarms()
         }
-        lifecycle.addObserver(obs)
-        onDispose { lifecycle.removeObserver(obs) }
     }
     return allowed
 }
diff --git a/app/src/main/java/de/jeanlucmakiola/agendula/ui/settings/SettingsViewModel.kt b/app/src/main/java/de/jeanlucmakiola/agendula/ui/settings/SettingsViewModel.kt
index e8d0614..b607be0 100644
--- a/app/src/main/java/de/jeanlucmakiola/agendula/ui/settings/SettingsViewModel.kt
+++ b/app/src/main/java/de/jeanlucmakiola/agendula/ui/settings/SettingsViewModel.kt
@@ -3,18 +3,27 @@ package de.jeanlucmakiola.agendula.ui.settings
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import dagger.hilt.android.lifecycle.HiltViewModel
+import de.jeanlucmakiola.agendula.data.di.IoDispatcher
 import de.jeanlucmakiola.agendula.data.prefs.Settings
 import de.jeanlucmakiola.agendula.data.prefs.SettingsPrefs
 import de.jeanlucmakiola.agendula.data.prefs.ThemeMode
+import de.jeanlucmakiola.agendula.data.tasks.ProviderEnvironment
+import de.jeanlucmakiola.agendula.data.tasks.ProviderResolver
+import de.jeanlucmakiola.agendula.data.tasks.StorageMode
+import de.jeanlucmakiola.agendula.data.tasks.TaskProvider
 import de.jeanlucmakiola.agendula.data.tasks.TasksRepository
 import de.jeanlucmakiola.agendula.data.tasks.recoveringFromProviderFailure
 import de.jeanlucmakiola.agendula.domain.TaskFormField
 import de.jeanlucmakiola.agendula.domain.TaskList
 import de.jeanlucmakiola.floret.reminders.ReminderOverride
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.flowOn
 import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.launch
 import javax.inject.Inject
 
@@ -23,6 +32,22 @@ data class SettingsUiState(
     val lists: List<TaskList> = emptyList(),
 )
 
+/**
+ * The storage half of Settings: which store is active, and what picking the
+ * other one would mean on this device.
+ *
+ * Kept apart from [SettingsUiState] because that one is collected for the whole
+ * Activity lifetime to drive the theme, and re-probing PackageManager on every
+ * theme emission would be work for nothing.
+ */
+data class StorageUiState(
+    val mode: StorageMode,
+    /** The external provider installed here, or null when there is none to pick. */
+    val external: TaskProvider? = null,
+    /** That provider's own app name, for a row that names what it is switching to. */
+    val externalLabel: String? = null,
+)
+
 /**
  * Drives both the Settings screen and the app theme (MainActivity collects the
  * same instance), so a theme change applies app-wide at once.
@@ -30,6 +55,9 @@ data class SettingsUiState(
 @HiltViewModel
 class SettingsViewModel @Inject constructor(
     private val prefs: SettingsPrefs,
+    private val resolver: ProviderResolver,
+    private val environment: ProviderEnvironment,
+    @IoDispatcher io: CoroutineDispatcher,
     repository: TasksRepository,
 ) : ViewModel() {
 
@@ -44,6 +72,31 @@ class SettingsViewModel @Inject constructor(
             SettingsUiState(settings, lists)
         }.stateIn(viewModelScope, SharingStarted.WhileSubscribed(5_000), SettingsUiState())
 
+    // Bumped to re-probe the device; installing a provider or granting its
+    // permission happens outside the app, so nothing else would emit.
+    private val providerProbe = MutableStateFlow(0)
+
+    // Null until the first emission lands: the mode comes from DataStore and the
+    // rest from PackageManager, off the main thread, so any seeded default would
+    // name the wrong store for the first frames. flowOn, because every field here
+    // costs a PackageManager lookup or a permission check.
+    val storage: StateFlow<StorageUiState?> =
+        combine(prefs.storageMode, providerProbe) { stored, _ ->
+            val external = resolver.resolveExternal()
+            StorageUiState(
+                // No stored choice is the normal state; show what autoMode resolves
+                // to rather than a default that may not be the store in use.
+                mode = stored ?: resolver.autoMode(),
+                external = external,
+                externalLabel = external?.packageName?.let(environment::appLabel),
+            )
+        }.flowOn(io).stateIn(viewModelScope, SharingStarted.WhileSubscribed(5_000), null)
+
+    /** Re-read the device's provider state, after a permission request or a resume. */
+    fun refreshStorage() = providerProbe.update { it + 1 }
+
+    fun setStorageMode(mode: StorageMode) = viewModelScope.launch { prefs.setStorageMode(mode) }
+
     fun setThemeMode(mode: ThemeMode) = viewModelScope.launch { prefs.setThemeMode(mode) }
     fun setDynamicColor(enabled: Boolean) = viewModelScope.launch { prefs.setDynamicColor(enabled) }
     fun setDefaultList(id: Long?) = viewModelScope.launch { prefs.setDefaultListId(id) }
diff --git a/app/src/main/java/de/jeanlucmakiola/agendula/ui/settings/StorageScreen.kt b/app/src/main/java/de/jeanlucmakiola/agendula/ui/settings/StorageScreen.kt
new file mode 100644
index 0000000..bc7c494
--- /dev/null
+++ b/app/src/main/java/de/jeanlucmakiola/agendula/ui/settings/StorageScreen.kt
@@ -0,0 +1,203 @@
+package de.jeanlucmakiola.agendula.ui.settings
+
+import android.content.Context
+import android.content.Intent
+import android.provider.Settings
+import androidx.activity.compose.rememberLauncherForActivityResult
+import androidx.activity.result.contract.ActivityResultContracts
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.rounded.Apps
+import androidx.compose.material.icons.rounded.PhoneAndroid
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import androidx.core.net.toUri
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import de.jeanlucmakiola.agendula.R
+import de.jeanlucmakiola.agendula.data.tasks.StorageMode
+import de.jeanlucmakiola.agendula.data.tasks.TaskProvider
+import de.jeanlucmakiola.agendula.ui.common.OnResume
+import de.jeanlucmakiola.floret.components.CollapsingScaffold
+import de.jeanlucmakiola.floret.components.FullScreenPicker
+import de.jeanlucmakiola.floret.components.GroupedRow
+import de.jeanlucmakiola.floret.components.Position
+import de.jeanlucmakiola.floret.components.SelectedCheck
+
+/**
+ * Where the tasks live: the store picker the resolver's `autoMode()` has always
+ * assumed, plus the way out of a store that lives in our own private storage.
+ */
+@Composable
+internal fun StorageScreen(
+    viewModel: SettingsViewModel,
+    onOpenExport: () -> Unit,
+    onBack: () -> Unit,
+) {
+    val context = LocalContext.current
+    val storage by viewModel.storage.collectAsStateWithLifecycle()
+    var showPicker by remember { mutableStateOf(false) }
+    var denied by remember { mutableStateOf(false) }
+
+    // The mode is committed only once the grant is in — switching first drops the
+    // user on the app-wide permission gate.
+    val permissionLauncher = rememberLauncherForActivityResult(
+        contract = ActivityResultContracts.RequestMultiplePermissions(),
+    ) { grants ->
+        viewModel.refreshStorage()
+        val granted = grants.isNotEmpty() && grants.values.all { it }
+        denied = !granted
+        if (granted) viewModel.setStorageMode(StorageMode.EXTERNAL)
+    }
+
+    // A provider can be installed, or its permission revoked, while we're away.
+    // Deliberately does not clear [denied]: this fires on returning from the
+    // permission dialog too, and would wipe the refusal before it is read.
+    OnResume { viewModel.refreshStorage() }
+
+    CollapsingScaffold(title = stringResource(R.string.settings_section_storage), onBack = onBack) {
+        GroupedRow(
+            title = stringResource(R.string.settings_task_store),
+            summary = storage?.let { storeLabel(it) },
+            position = Position.Top,
+            // Nothing to pick until the stored mode has landed; opening the picker
+            // on the seeded state would offer the wrong store as the current one.
+            onClick = storage?.let {
+                {
+                    denied = false
+                    showPicker = true
+                }
+            },
+        )
+        GroupedRow(
+            title = stringResource(R.string.settings_export),
+            summary = stringResource(R.string.settings_export_hint),
+            position = Position.Bottom,
+            onClick = onOpenExport,
+        )
+
+        if (denied) {
+            Spacer(Modifier.height(16.dp))
+            GroupedRow(
+                title = stringResource(R.string.settings_store_permission_denied),
+                summary = stringResource(R.string.settings_store_permission_denied_hint),
+                position = Position.Alone,
+                onClick = { context.openAppSettings() },
+            )
+        }
+    }
+
+    storage?.let { state ->
+        if (showPicker) {
+            StorePicker(
+                storage = state,
+                onSelect = { mode ->
+                    val external = state.external
+                    if (mode == StorageMode.EXTERNAL && external != null) {
+                        // Asked even when the grant looks held: an already-granted
+                        // request returns at once, a stale belief would strand them.
+                        permissionLauncher.launch(
+                            arrayOf(external.readPermission, external.writePermission),
+                        )
+                    } else {
+                        viewModel.setStorageMode(mode)
+                    }
+                },
+                onDismiss = { showPicker = false },
+            )
+        }
+    }
+}
+
+/**
+ * The two stores, as rows. External is offered only when a provider is actually
+ * installed — dimmed and inert otherwise, because a mode with nothing behind it
+ * empties the app.
+ */
+@Composable
+private fun StorePicker(
+    storage: StorageUiState,
+    onSelect: (StorageMode) -> Unit,
+    onDismiss: () -> Unit,
+) {
+    FullScreenPicker(title = stringResource(R.string.settings_task_store), onDismiss = onDismiss) {
+        Text(
+            text = stringResource(R.string.settings_task_store_hint),
+            style = MaterialTheme.typography.bodyMedium,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+            modifier = Modifier.padding(horizontal = 16.dp, vertical = 4.dp),
+        )
+        Spacer(Modifier.height(8.dp))
+
+        val select: (StorageMode) -> Unit = { chosen ->
+            onSelect(chosen)
+            onDismiss()
+        }
+        val external = storage.external
+        GroupedRow(
+            title = stringResource(R.string.settings_store_own),
+            summary = stringResource(R.string.settings_store_own_hint),
+            position = Position.Top,
+            selected = storage.mode == StorageMode.OWN,
+            leading = { Icon(Icons.Rounded.PhoneAndroid, contentDescription = null) },
+            trailing = if (storage.mode == StorageMode.OWN) {
+                { SelectedCheck() }
+            } else {
+                null
+            },
+            onClick = { select(StorageMode.OWN) },
+        )
+        GroupedRow(
+            title = externalTitle(external, storage.externalLabel),
+            summary = stringResource(
+                if (external == null) {
+                    R.string.settings_store_external_missing
+                } else {
+                    R.string.settings_store_external_hint
+                },
+            ),
+            position = Position.Bottom,
+            selected = storage.mode == StorageMode.EXTERNAL,
+            dimmed = external == null,
+            leading = { Icon(Icons.Rounded.Apps, contentDescription = null) },
+            trailing = if (storage.mode == StorageMode.EXTERNAL) {
+                { SelectedCheck() }
+            } else {
+                null
+            },
+            onClick = if (external != null) ({ select(StorageMode.EXTERNAL) }) else null,
+        )
+        Spacer(Modifier.height(24.dp))
+    }
+}
+
+/** The active store, named the way the picker names it. */
+@Composable
+private fun storeLabel(storage: StorageUiState): String = when (storage.mode) {
+    StorageMode.OWN -> stringResource(R.string.settings_store_own)
+    StorageMode.EXTERNAL -> externalTitle(storage.external, storage.externalLabel)
+}
+
+/** The provider's own app name, its authority, or the generic wording. */
+@Composable
+private fun externalTitle(provider: TaskProvider?, label: String?): String =
+    label ?: provider?.authority ?: stringResource(R.string.settings_store_external)
+
+private fun Context.openAppSettings() {
+    runCatching {
+        startActivity(
+            Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS, "package:$packageName".toUri()),
+        )
+    }
+}
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 1a6beca..dd0c5a8 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -246,6 +246,37 @@
     <string name="settings_bottom_add_bar">Bottom quick-add bar</string>
     <string name="settings_bottom_add_bar_hint">Add tasks from a bar pinned to the bottom of a list, instead of the floating button</string>
 
+    <string name="onboarding_use_own_store">Use this device\'s storage instead</string>
+
+    <!-- Storage and export -->
+    <string name="settings_section_storage">Storage</string>
+    <string name="settings_storage_subtitle">Where tasks are kept, and export</string>
+    <string name="settings_task_store">Task store</string>
+    <string name="settings_task_store_hint">Each store keeps its own tasks. Switching does not move them across — export first if you want a copy.</string>
+    <string name="settings_store_own">On this device</string>
+    <string name="settings_store_own_hint">Agendula\'s own storage. Nothing else to install.</string>
+    <string name="settings_store_external">Another task app</string>
+    <string name="settings_store_external_hint">Share tasks with the app that syncs them</string>
+    <string name="settings_store_external_missing">No compatible task app is installed</string>
+    <string name="settings_store_permission_denied">Permission denied</string>
+    <string name="settings_store_permission_denied_hint">The other app\'s tasks stay unreachable until you allow access. Tap to open app settings.</string>
+    <string name="settings_export">Export tasks</string>
+    <string name="settings_export_hint">Save your lists as iCalendar files</string>
+    <string name="export_hint">One .ics file per list, readable by other task and calendar apps. The ticked lists go to a folder you pick, or into a single zip.</string>
+    <string name="export_no_lists">No lists to export</string>
+    <string name="export_to_folder">Save to a folder</string>
+    <string name="export_to_zip">Save as a zip file</string>
+    <string name="export_running">Exporting…</string>
+    <plurals name="export_done">
+        <item quantity="one">Exported %1$d list</item>
+        <item quantity="other">Exported %1$d lists</item>
+    </plurals>
+    <string name="export_failed">The export could not be written</string>
+    <string name="export_failed_folder">The chosen folder could not be opened</string>
+    <string name="export_failed_read_only">The chosen folder is not writable</string>
+    <string name="export_failed_create">A file could not be created in the chosen folder</string>
+    <string name="export_failed_access">Access to the chosen location was lost</string>
+
     <!-- Reminder lead times (custom amounts) -->
     <plurals name="reminder_minutes">
         <item quantity="one">%1$d minute before</item>
diff --git a/app/src/test/java/de/jeanlucmakiola/agendula/data/tasks/ProviderResolverTest.kt b/app/src/test/java/de/jeanlucmakiola/agendula/data/tasks/ProviderResolverTest.kt
index 9d7a988..c73eb3f 100644
--- a/app/src/test/java/de/jeanlucmakiola/agendula/data/tasks/ProviderResolverTest.kt
+++ b/app/src/test/java/de/jeanlucmakiola/agendula/data/tasks/ProviderResolverTest.kt
@@ -23,6 +23,7 @@ class ProviderResolverTest {
     ) : ProviderEnvironment {
         override fun packageDeclaring(authority: String): String? = installed[authority]
         override fun isGranted(permission: String): Boolean = permission in granted
+        override fun appLabel(packageName: String): String? = packageName
     }
 
     private val openTasks = ProviderResolver.EXTERNAL_CANDIDATES.first { it.authority == "org.dmfs.tasks" }
diff --git a/docs/ARCHITECTURE.md b/docs/ARCHITECTURE.md
index c216fb7..1d27981 100644
--- a/docs/ARCHITECTURE.md
+++ b/docs/ARCHITECTURE.md
@@ -108,7 +108,7 @@ postscript in [`STORAGE-DECISION.md`](STORAGE-DECISION.md). Package root
 | `data/prefs/` | `SettingsPrefs` (DataStore). |
 | `data/di/` | `DataModule` (binds + provides), `Qualifiers` (`@IoDispatcher`, `@ApplicationScope`). |
 | `data/demo/` | `DemoSeeder` (debug-only sample data). |
-| `ui/` | `theme/`, `common/` (ListChip, PriorityChip, reminder pickers), `navigation/` (`AgendulaNavHost` + `Dest`), `lists/`, `tasklist/`, `detail/`, `edit/`, `settings/`, `permission/` (each a screen + ViewModel + UiState), `crash/`, `RootScreen`. |
+| `ui/` | `theme/`, `common/` (ListChip, PriorityChip, reminder pickers), `navigation/` (`AgendulaNavHost` + `Dest`), `lists/`, `tasklist/`, `detail/`, `edit/`, `settings/` (hub + sub-screens, `StorageScreen` among them), `export/`, `permission/` (each a screen + ViewModel + UiState), `crash/`, `RootScreen`. |
 | root | `AgendulaApp` (Hilt app), `MainActivity`. |
 
 ---
@@ -447,10 +447,21 @@ fallback in `ui/theme/`). Each screen area (`lists`, `tasklist`, `detail`,
 `RootScreen` is the entry composable: it gates on `ProviderStatus`
 (`NO_PROVIDER` / `NEEDS_PERMISSION` → onboarding `Gate`; `READY` →
 `AgendulaNavHost`). In `OWN` mode the status is always `READY`, so that gate is
-only ever seen in External mode. Routes are the `Dest` table in
-`ui/navigation/` (lists → task list → detail / edit, plus settings). Follow the
-`material-3` skill for component choices (M3 `ListItem` rows, expressive
-checkbox/FAB/swipe motion).
+only ever seen in External mode — and it offers a way back to our own store,
+because it is the only screen an External user can reach once their provider app
+stops answering. Routes are the `Dest` table in `ui/navigation/` (lists → task
+list → detail / edit, plus settings). Follow the `material-3` skill for component
+choices (M3 `ListItem` rows, expressive checkbox/FAB/swipe motion).
+
+Settings is a hub of sliding sub-screens rather than routes; **Storage** is the
+one with teeth. It holds the §4.1 store picker — which asks for an external
+provider's runtime permission *before* writing the mode, so a denial leaves the
+readable store in place instead of stranding the user on the gate — and the
+export screen (`ui/export/`, one `.ics` per ticked list, written through SAF to a
+folder or a single zip). Because the mode is now switchable while the process
+lives, `AgendulaApp` re-arms reminders on `ProviderResolver.onModeChanged`: an
+alarm is scheduled off whichever store was active at the time, so the whole set
+has to be rebuilt against the new one.
 
 ---
 
diff --git a/docs/ROADMAP.md b/docs/ROADMAP.md
index a73b09f..945d92b 100644
--- a/docs/ROADMAP.md
+++ b/docs/ROADMAP.md
@@ -19,10 +19,11 @@ iCalendar has landed, and the Material 3 Expressive UI is built through **M5**:
 lists → task list (swipe gestures, inline add, smart-list section headers) →
 detail / edit with full CRUD, date-time pickers, priority, percent-complete,
 conflict-safe saves, per-task reminders, and subtask create + reparent — plus a
-one-time reminder onboarding step and a Settings screen. Remaining work is
-hardening the new store (`OWN-STORE.md` phase 6), the **frontend surfaces for
-what has landed** (a storage-mode picker, an export screen), then M6 (Glance
-widget, translations, F-Droid release) and the sync adapter.
+one-time reminder onboarding step and a Settings screen. The frontend surfaces
+for the new store have landed too: a Settings **Storage** section with the
+store picker and an **export screen**. Remaining work is verifying all of it on
+a device, then M6 (Glance widget, translations, F-Droid release) and the sync
+adapter.
 
 ---
 
@@ -147,8 +148,17 @@ what Posture B means (our own store, coexisting with everything — *not* squatt
 - ✅ Export to iCalendar (step 3) — a v1 feature now that own-mode data lives
   only in our app's private storage. One `.ics` per list, to a folder or a zip,
   via SAF. Backend only.
-- ⬜ **Frontend surfaces for the above** — a storage-mode picker in Settings and
-  an export screen. The backend is done and unused until these exist.
+- ✅ **Frontend surfaces for the above** — Settings gained a **Storage** section
+  holding both: a full-screen store picker (Own / an installed external provider,
+  which is dimmed when none is present) that asks for the provider's runtime
+  permission *before* committing the switch, and an export screen with a per-list
+  tick and the two SAF destinations, a folder or a single zip. Two consequences
+  of the mode becoming switchable at runtime came with it: reminders are re-armed
+  against the new store on every switch (`AgendulaApp` listens on
+  `ProviderResolver.onModeChanged`; previously only a restart, a boot or an edit
+  resynced them), and the permission gate offers a way back to our own store —
+  otherwise a user whose provider app went away is held on a gate with Settings
+  behind it.
 - ⬜ File the DAVx5 issue (step 4) — non-blocking, cheap, serves F-Droid users.
   Note it now means "sync into an app that has no provider", so the ask has
   changed shape.
@@ -264,9 +274,9 @@ These carry over from [`PLAN.md`](PLAN.md) §9; resolved ones are struck through
    resolved: our own store expands a series at read time and writes an edit to
    one occurrence as a `RECURRENCE-ID` override sharing the master's UID; in
    External mode the edit still goes through the instances URI.
-6. **Resolver ordering / mode-selection UX** — `autoMode()` picks a sane default
-   today (see [`ARCHITECTURE.md`](ARCHITECTURE.md) §4.1); the Settings override it
-   assumes is not built yet.
+6. ~~**Resolver ordering / mode-selection UX**~~ resolved: `autoMode()` picks the
+   default (see [`ARCHITECTURE.md`](ARCHITECTURE.md) §4.1) and Settings → Storage
+   → Task store is the override it always assumed.
 7. ~~**Sync protocol coverage**, account model, conflict resolution — the next
    design discussion.~~ Taken up in [`SYNC.md`](SYNC.md); the remaining opens
    live on that document's list.
diff --git a/docs/STORAGE-AND-SYNC.md b/docs/STORAGE-AND-SYNC.md
index 4cfb065..7224a45 100644
--- a/docs/STORAGE-AND-SYNC.md
+++ b/docs/STORAGE-AND-SYNC.md
@@ -42,7 +42,7 @@
 |---|---|---|---|
 | 1 | Merge `fix/provider-interaction-review` | unmerged and rotting; touches the same permission flow as step 2 | ✅ done |
 | 2 | Vendor `:provider` under our own authority | the identity, done once — and it ships a complete local-first app | ✅ done |
-| 3 | Export / backup | our data now lives only in our app's private storage | ✅ backend done; no UI yet |
+| 3 | Export / backup | our data now lives only in our app's private storage | ✅ done, UI included |
 | 4 | File the DAVx5 issue | cheap, non-blocking, serves F-Droid users | ⬜ |
 | 5 | Sync adapter | the 1.x arc; designed in [`SYNC.md`](SYNC.md), not yet built | ⬜ |
 
@@ -202,8 +202,9 @@ than "rank ours first whenever it's non-empty", and needs no database probe:
 
 That permission is dangerous-level, so it can only be there because an earlier
 version asked and the user agreed — which is exactly what "existing Posture A
-user" means. A fresh install holds nothing and gets local-first. ⬜ The Settings
-override the rule assumes is not built yet.
+user" means. A fresh install holds nothing and gets local-first. ✅ The Settings
+override the rule assumes is built: Storage → Task store, which asks for the
+external provider's permission before committing the switch rather than after.
 
 **Note on the mode vocabulary.** The code has two modes, not three:
 `StorageMode.LOCAL` and `StorageMode.EXTERNAL`. As this document says two
@@ -211,7 +212,7 @@ paragraphs up, Synced *is* Local with an account attached — so it is derived
 state, and giving it its own constant would imply switching sync on is a
 migration when the whole point is that it isn't.
 
-**Export/backup is a v1 feature.** ✅ Backend built (no UI yet). Not, as
+**Export/backup is a v1 feature.** ✅ Built, screen included. Not, as
 previously framed, a migration safety net for "uninstall OpenTasks" — that
 scenario no longer exists. It's data portability for Local-mode users, whose
 tasks otherwise exist in exactly one place with no second copy. On Play, where