diff --git a/CHANGELOG.md b/CHANGELOG.md
index c887e30..e278004 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -38,9 +38,11 @@ The first release of Clockula: alarms, timers, a stopwatch and a world clock.
   timer turns the screen on and opens over the lock screen with Stop and
   +1 min. Timers keep counting through a reboot and aren't affected by changes
   to the clock.
-- Timers have their own vibration switch, off by default, and an optional
-  gradual volume, both apart from the alarms'. A kitchen timer can just beep
-  while alarms still vibrate; a silent timer still vibrates.
+- Timers have their own vibration switch and an optional gradual volume, both
+  apart from the alarms'. A kitchen timer can just beep while alarms still
+  vibrate; a silent timer still vibrates. New installs start with timer
+  vibration off; an updated install keeps vibrating its timers if it did
+  before.
 - **Stopwatch** with laps, the fastest and slowest marked, and Lap and Pause
   in the notification. It keeps counting while the app is closed.
 - **World clock.** An analog face for your own time, plus cities from the
diff --git a/app/src/main/java/de/jeanlucmakiola/clockula/ClockulaApp.kt b/app/src/main/java/de/jeanlucmakiola/clockula/ClockulaApp.kt
index 9953f26..5945f12 100644
--- a/app/src/main/java/de/jeanlucmakiola/clockula/ClockulaApp.kt
+++ b/app/src/main/java/de/jeanlucmakiola/clockula/ClockulaApp.kt
@@ -105,7 +105,9 @@ class ClockulaApp : Application() {
         } catch (cancelled: CancellationException) {
             throw cancelled
         } catch (_: Exception) {
-            // Unsettled is safe; the next launch tries again.
+            // Unsettled reads as the old behaviour. The next launch tries again,
+            // and by then the store is no longer empty, so even a fresh install
+            // settles on the alarm default: vibrating, the safe side to err on.
         }
     }
 
diff --git a/app/src/main/java/de/jeanlucmakiola/clockula/data/prefs/SettingsPrefs.kt b/app/src/main/java/de/jeanlucmakiola/clockula/data/prefs/SettingsPrefs.kt
index 977db31..bed61f8 100644
--- a/app/src/main/java/de/jeanlucmakiola/clockula/data/prefs/SettingsPrefs.kt
+++ b/app/src/main/java/de/jeanlucmakiola/clockula/data/prefs/SettingsPrefs.kt
@@ -1,5 +1,7 @@
 package de.jeanlucmakiola.clockula.data.prefs
 
+import androidx.datastore.preferences.core.booleanPreferencesKey
+import androidx.datastore.preferences.core.stringPreferencesKey
 import de.jeanlucmakiola.clockula.domain.ClockDefaults
 import de.jeanlucmakiola.clockula.domain.DismissChallenge
 import de.jeanlucmakiola.clockula.domain.backup.BackupSettings
@@ -135,10 +137,16 @@ class SettingsPrefs @Inject constructor(private val store: PrefStore) {
      * side's fallback keeps the old behaviour, so a failed write costs nothing.
      */
     suspend fun settleTimerVibrate(freshInstall: Boolean) {
-        val untouched = store.data.first().asMap().isEmpty()
-        val alarmVibrate = store.get(ClockPrefs.vibrate)
-        store.update(ClockPrefs.timerVibrate) { stored ->
-            stored ?: if (untouched && freshInstall) false else alarmVibrate
+        // One transaction, so nothing written meanwhile can make the snapshot
+        // it decides on stale. Raw keys for the reads: the kit reads a Pref
+        // only from a store, not from a transaction's preferences.
+        store.edit { prefs ->
+            if (stringPreferencesKey(ClockPrefs.timerVibrate.name) in prefs) return@edit
+            prefs[ClockPrefs.timerVibrate] = if (prefs.asMap().isEmpty() && freshInstall) {
+                false
+            } else {
+                prefs[booleanPreferencesKey(ClockPrefs.vibrate.name)] ?: ClockPrefs.vibrate.default
+            }
         }
     }
 
diff --git a/app/src/main/java/de/jeanlucmakiola/clockula/ui/settings/TimerDefaultsScreen.kt b/app/src/main/java/de/jeanlucmakiola/clockula/ui/settings/TimerDefaultsScreen.kt
index be6aca0..2d7c659 100644
--- a/app/src/main/java/de/jeanlucmakiola/clockula/ui/settings/TimerDefaultsScreen.kt
+++ b/app/src/main/java/de/jeanlucmakiola/clockula/ui/settings/TimerDefaultsScreen.kt
@@ -10,6 +10,11 @@ import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.semantics.Role
+import androidx.compose.ui.semantics.role
+import androidx.compose.ui.semantics.semantics
+import androidx.compose.ui.semantics.toggleableState
+import androidx.compose.ui.state.ToggleableState
 import androidx.compose.ui.unit.dp
 import de.jeanlucmakiola.clockula.R
 import de.jeanlucmakiola.clockula.ui.alarms.VolumeRampPicker
@@ -49,6 +54,11 @@ internal fun TimerDefaultsScreen(
         // what the ring does with Silent and vibration both off: vibrates anyway.
         GroupedRow(
             title = stringResource(R.string.editor_vibrate),
+            // The switch below is display-only, so the row carries its role and state.
+            modifier = Modifier.semantics {
+                role = Role.Switch
+                toggleableState = ToggleableState(defaults.timerVibrate)
+            },
             summary = if (defaults.timerVibrate) {
                 vibrateText(on = true)
             } else {
@@ -57,7 +67,7 @@ internal fun TimerDefaultsScreen(
             position = Position.Middle,
             trailing = {
                 // Display only: the row is the one control, so a screen reader
-                // stops on it once rather than on the row and then the switch.
+                // stops once, on a row announced as a switch.
                 Switch(checked = defaults.timerVibrate, onCheckedChange = null)
             },
             onClick = { viewModel.onTimerVibrateChanged(!defaults.timerVibrate) },