diff --git a/app/src/androidTest/kotlin/org/libremail/ui/onboarding/BatteryOptimizationStepTest.kt b/app/src/androidTest/kotlin/org/libremail/ui/onboarding/BatteryOptimizationStepTest.kt
index a0b0852..99d8c95 100644
--- a/app/src/androidTest/kotlin/org/libremail/ui/onboarding/BatteryOptimizationStepTest.kt
+++ b/app/src/androidTest/kotlin/org/libremail/ui/onboarding/BatteryOptimizationStepTest.kt
@@ -13,6 +13,7 @@ import androidx.compose.ui.test.junit4.createAndroidComposeRule
 import androidx.compose.ui.test.onAllNodesWithText
 import androidx.compose.ui.test.onNodeWithText
 import androidx.compose.ui.test.performClick
+import androidx.lifecycle.SavedStateHandle
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.navigation.NavType
 import androidx.navigation.compose.NavHost
@@ -75,6 +76,7 @@ class BatteryOptimizationStepTest {
             BatteryOptimizationManager(context),
             ContactsPermissionManager(context),
             settingsRepository,
+            SavedStateHandle(),
         )
         onboarding.onAccountAdded(FIRST_ACCOUNT_ID)
 
diff --git a/app/src/androidTest/kotlin/org/libremail/ui/onboarding/OnboardingFlowTest.kt b/app/src/androidTest/kotlin/org/libremail/ui/onboarding/OnboardingFlowTest.kt
index 52eb3a8..6e7ef6f 100644
--- a/app/src/androidTest/kotlin/org/libremail/ui/onboarding/OnboardingFlowTest.kt
+++ b/app/src/androidTest/kotlin/org/libremail/ui/onboarding/OnboardingFlowTest.kt
@@ -110,6 +110,7 @@ class OnboardingFlowTest {
             BatteryOptimizationManager(appContext),
             ContactsPermissionManager(appContext),
             SettingsRepository(appContext),
+            SavedStateHandle(),
         )
         composeTestRule.setContent {
             LibreMailTheme(darkTheme = false, dynamicColor = false) {
diff --git a/app/src/main/kotlin/org/libremail/ui/accountsetup/AccountSetupViewModel.kt b/app/src/main/kotlin/org/libremail/ui/accountsetup/AccountSetupViewModel.kt
index 48e63f8..1ffdf01 100644
--- a/app/src/main/kotlin/org/libremail/ui/accountsetup/AccountSetupViewModel.kt
+++ b/app/src/main/kotlin/org/libremail/ui/accountsetup/AccountSetupViewModel.kt
@@ -63,7 +63,10 @@ class AccountSetupViewModel @Inject constructor(
 
     fun onOutlookResult(data: Intent?) {
         if (data == null) {
-            _state.update { it.copy(error = "Microsoft sign-in was cancelled") }
+            // A null result Intent is a normal user cancel: backing out of the Microsoft sign-in tab
+            // returns RESULT_CANCELED with no data. That is expected, not a failure, so it is a no-op —
+            // surfacing an error snackbar for a deliberate cancel is just noise (#308).
+            AppLog.d(TAG, "Outlook sign-in cancelled by the user; no-op")
             return
         }
         viewModelScope.launch {
diff --git a/app/src/main/kotlin/org/libremail/ui/compose/RichTextEditor.kt b/app/src/main/kotlin/org/libremail/ui/compose/RichTextEditor.kt
index cc48459..c7064bf 100644
--- a/app/src/main/kotlin/org/libremail/ui/compose/RichTextEditor.kt
+++ b/app/src/main/kotlin/org/libremail/ui/compose/RichTextEditor.kt
@@ -262,9 +262,10 @@ private fun FormattingToolbar(
     onFont: (String?) -> Unit,
     onInsertImage: (() -> Unit)?,
 ) {
-    val content = value.annotatedString.toRichContent()
-    val start = value.selection.min
-    val end = value.selection.max
+    // Parsing the field into RichTextContent and the dozen selection scans that light up the buttons is
+    // a per-keystroke hot path; memoize the whole derivation on the field value so a recomposition that
+    // doesn't change it reuses the result instead of re-parsing + re-scanning (#308).
+    val toolbar = remember(value) { toolbarStateOf(value) }
     Row(
         modifier = Modifier
             .fillMaxWidth()
@@ -276,63 +277,61 @@ private fun FormattingToolbar(
         FormatButton(
             label = "B",
             description = stringResource(R.string.format_bold),
-            active = RichTextEditing.isStyled(content, start, end, RichStyle.Bold),
+            active = toolbar.bold,
             fontWeight = FontWeight.Bold,
             onClick = { onToggleStyle(RichStyle.Bold) },
         )
         FormatButton(
             label = "I",
             description = stringResource(R.string.format_italic),
-            active = RichTextEditing.isStyled(content, start, end, RichStyle.Italic),
+            active = toolbar.italic,
             fontStyle = FontStyle.Italic,
             onClick = { onToggleStyle(RichStyle.Italic) },
         )
         FormatButton(
             label = "U",
             description = stringResource(R.string.format_underline),
-            active = RichTextEditing.isStyled(content, start, end, RichStyle.Underline),
+            active = toolbar.underline,
             underline = true,
             onClick = { onToggleStyle(RichStyle.Underline) },
         )
         FormatButton(
             label = "S",
             description = stringResource(R.string.format_strikethrough),
-            active = RichTextEditing.isStyled(content, start, end, RichStyle.Strikethrough),
+            active = toolbar.strikethrough,
             strikethrough = true,
             onClick = { onToggleStyle(RichStyle.Strikethrough) },
         )
-        val fontColorArgb = RichTextEditing.styleAt(content, start, end, RichStyle.FontColor::class.java)?.argb
         FormatButton(
             label = "A",
             description = stringResource(R.string.format_color),
-            active = fontColorArgb != null,
-            tint = fontColorArgb?.let { Color(it) },
+            active = toolbar.fontColorArgb != null,
+            tint = toolbar.fontColorArgb?.let { Color(it) },
             onClick = onFontColor,
         )
-        val highlightArgb = RichTextEditing.styleAt(content, start, end, RichStyle.Highlight::class.java)?.argb
         FormatButton(
             label = "H",
             description = stringResource(R.string.format_highlight),
             active = false,
-            swatchColor = highlightArgb?.let { Color(it) },
+            swatchColor = toolbar.highlightArgb?.let { Color(it) },
             onClick = onHighlight,
         )
         FormatButton(
             label = "•",
             description = stringResource(R.string.format_bullet_list),
-            active = RichTextEditing.hasBlock(content, start, end, BlockMarker.BULLET),
+            active = toolbar.bullet,
             onClick = { onToggleBlock(BlockMarker.BULLET) },
         )
         FormatButton(
             label = "1.",
             description = stringResource(R.string.format_numbered_list),
-            active = RichTextEditing.hasBlock(content, start, end, BlockMarker.ORDERED),
+            active = toolbar.ordered,
             onClick = { onToggleBlock(BlockMarker.ORDERED) },
         )
         FormatButton(
             label = "❝",
             description = stringResource(R.string.format_quote),
-            active = RichTextEditing.hasBlock(content, start, end, BlockMarker.QUOTE),
+            active = toolbar.quote,
             onClick = { onToggleBlock(BlockMarker.QUOTE) },
         )
         FormatButton(
@@ -347,12 +346,10 @@ private fun FormattingToolbar(
         // so its click lands on the button's on-screen center. Any control inserted *before* the block
         // buttons shifts them right and can push the bullet past the viewport, making that tap miss —
         // so these wider controls are appended last, leaving every pre-existing button in its tested spot.
-        val fontCss = RichTextEditing.styleAt(content, start, end, RichStyle.FontFamily::class.java)?.css
-        FontPicker(selectedCss = fontCss, onSelect = onFont)
-        val fontSizePt = RichTextEditing.styleAt(content, start, end, RichStyle.FontSize::class.java)?.pt
-        FontSizePicker(selectedPt = fontSizePt, onSelect = onFontSize)
+        FontPicker(selectedCss = toolbar.fontCss, onSelect = onFont)
+        FontSizePicker(selectedPt = toolbar.fontSizePt, onSelect = onFontSize)
         ParagraphAlignmentControl(
-            selected = RichTextEditing.alignmentAt(content, start, end),
+            selected = toolbar.alignment,
             onSelect = onAlignment,
         )
         // The image button is appended last (like the other trailing controls) so it never shifts the
@@ -368,6 +365,53 @@ private fun FormattingToolbar(
     }
 }
 
+/**
+ * The [FormattingToolbar]'s button state derived from the field's current [TextFieldValue]: the
+ * active/inactive toggles plus the currently-applied color/font/size/alignment the pickers read back.
+ * Bundled so the parse + selection scans that produce them can be computed once per field value and
+ * memoized, keeping the per-keystroke toolbar off the re-parse-everything path (#308).
+ */
+internal data class ToolbarState(
+    val bold: Boolean,
+    val italic: Boolean,
+    val underline: Boolean,
+    val strikethrough: Boolean,
+    val fontColorArgb: Int?,
+    val highlightArgb: Int?,
+    val bullet: Boolean,
+    val ordered: Boolean,
+    val quote: Boolean,
+    val fontCss: String?,
+    val fontSizePt: Int?,
+    val alignment: RichAlign?,
+)
+
+/**
+ * Parses [value] into [RichTextContent] once and runs every toolbar selection scan over that single
+ * parse, so [FormattingToolbar] derives all its button state in one pass instead of re-parsing the
+ * whole body and re-scanning per button on each recomposition (#308). Pure over plain
+ * [TextFieldValue] so it is JVM-unit-testable.
+ */
+internal fun toolbarStateOf(value: TextFieldValue): ToolbarState {
+    val content = value.annotatedString.toRichContent()
+    val start = value.selection.min
+    val end = value.selection.max
+    return ToolbarState(
+        bold = RichTextEditing.isStyled(content, start, end, RichStyle.Bold),
+        italic = RichTextEditing.isStyled(content, start, end, RichStyle.Italic),
+        underline = RichTextEditing.isStyled(content, start, end, RichStyle.Underline),
+        strikethrough = RichTextEditing.isStyled(content, start, end, RichStyle.Strikethrough),
+        fontColorArgb = RichTextEditing.styleAt(content, start, end, RichStyle.FontColor::class.java)?.argb,
+        highlightArgb = RichTextEditing.styleAt(content, start, end, RichStyle.Highlight::class.java)?.argb,
+        bullet = RichTextEditing.hasBlock(content, start, end, BlockMarker.BULLET),
+        ordered = RichTextEditing.hasBlock(content, start, end, BlockMarker.ORDERED),
+        quote = RichTextEditing.hasBlock(content, start, end, BlockMarker.QUOTE),
+        fontCss = RichTextEditing.styleAt(content, start, end, RichStyle.FontFamily::class.java)?.css,
+        fontSizePt = RichTextEditing.styleAt(content, start, end, RichStyle.FontSize::class.java)?.pt,
+        alignment = RichTextEditing.alignmentAt(content, start, end),
+    )
+}
+
 @Composable
 private fun FormatButton(
     label: String,
diff --git a/app/src/main/kotlin/org/libremail/ui/lock/AppLockGateHost.kt b/app/src/main/kotlin/org/libremail/ui/lock/AppLockGateHost.kt
index a45cc01..b2c7ebe 100644
--- a/app/src/main/kotlin/org/libremail/ui/lock/AppLockGateHost.kt
+++ b/app/src/main/kotlin/org/libremail/ui/lock/AppLockGateHost.kt
@@ -16,6 +16,7 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.input.pointer.pointerInput
 import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.semantics.clearAndSetSemantics
 import androidx.core.content.ContextCompat
 import androidx.fragment.app.FragmentActivity
 import androidx.hilt.lifecycle.viewmodel.compose.hiltViewModel
@@ -70,7 +71,21 @@ fun AppLockGateHost(viewModel: AppLockViewModel = hiltViewModel(), content: @Com
     LaunchedEffect(uiState) { if (uiState is AppLockUiState.Unlocked) hasEverUnlocked = true }
 
     Box(modifier = Modifier.fillMaxSize()) {
-        if (hasEverUnlocked) content()
+        // While the app is covered (Checking/Locked) the opaque LockCover hides the content visually and
+        // blocks its input, but the content stays in the composition (so its state survives a re-lock).
+        // Clear the covered subtree out of the semantics/accessibility tree so an accessibility service
+        // (e.g. TalkBack) can't traverse the occluded mailbox/compose nodes behind the cover (#308). When
+        // Unlocked the modifier is dropped, restoring the content's full semantics.
+        val contentCovered = uiState !is AppLockUiState.Unlocked
+        Box(
+            modifier = if (contentCovered) {
+                Modifier.fillMaxSize().clearAndSetSemantics { }
+            } else {
+                Modifier.fillMaxSize()
+            },
+        ) {
+            if (hasEverUnlocked) content()
+        }
 
         when (val state = uiState) {
             AppLockUiState.Unlocked -> Unit
diff --git a/app/src/main/kotlin/org/libremail/ui/onboarding/OnboardingViewModel.kt b/app/src/main/kotlin/org/libremail/ui/onboarding/OnboardingViewModel.kt
index 079e31b..0a7408b 100644
--- a/app/src/main/kotlin/org/libremail/ui/onboarding/OnboardingViewModel.kt
+++ b/app/src/main/kotlin/org/libremail/ui/onboarding/OnboardingViewModel.kt
@@ -2,6 +2,7 @@
 package org.libremail.ui.onboarding
 
 import android.content.Intent
+import androidx.lifecycle.SavedStateHandle
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import dagger.hilt.android.lifecycle.HiltViewModel
@@ -13,6 +14,8 @@ import org.libremail.contacts.ContactsPermissionManager
 import org.libremail.data.settings.SettingsRepository
 import org.libremail.push.BatteryOptimizationManager
 import org.libremail.push.BatteryPromptDecision
+import org.libremail.reporting.AppLog
+import org.libremail.reporting.accountLogRef
 import javax.inject.Inject
 
 /**
@@ -28,11 +31,18 @@ class OnboardingViewModel @Inject constructor(
     private val batteryOptimizationManager: BatteryOptimizationManager,
     private val contactsPermissionManager: ContactsPermissionManager,
     private val settingsRepository: SettingsRepository,
+    private val savedStateHandle: SavedStateHandle,
 ) : ViewModel() {
 
-    /** The id of the first account added this session, or null if none has been added yet. */
-    var firstAddedAccountId: String? = null
-        private set
+    /**
+     * The id of the first account added this session, or null if none has been added yet. Held in
+     * [SavedStateHandle] rather than a plain field so it survives process death: this ViewModel is
+     * scoped to the onboarding nav-graph back-stack entry, whose saved state is restored after a
+     * process kill. Without that, a kill mid-onboarding — e.g. the excursion to system battery
+     * settings on the opt-in step — would drop the id and finish onto the unfiltered mailbox instead
+     * of the first account's inbox, defeating #30.
+     */
+    val firstAddedAccountId: String? get() = savedStateHandle[KEY_FIRST_ACCOUNT_ID]
 
     private val _batteryPromptNeeded = MutableStateFlow<Boolean?>(null)
 
@@ -82,7 +92,9 @@ class OnboardingViewModel @Inject constructor(
     /** Records a freshly added account. Only the first one sticks — later adds don't overwrite it. */
     fun onAccountAdded(accountId: String) {
         if (firstAddedAccountId == null) {
-            firstAddedAccountId = accountId
+            savedStateHandle[KEY_FIRST_ACCOUNT_ID] = accountId
+            // PII-free: the id embeds the email, so reference it only via its non-reversible log ref.
+            AppLog.i(TAG, "onboarding recorded first account ${accountLogRef(accountId)}")
         }
     }
 
@@ -128,4 +140,11 @@ class OnboardingViewModel @Inject constructor(
     fun markContactsPromptHandled() {
         viewModelScope.launch { settingsRepository.setContactsPromptHandled(true) }
     }
+
+    private companion object {
+        const val TAG = "OnboardingVM"
+
+        /** SavedStateHandle key for [firstAddedAccountId], persisted across process death (#308). */
+        const val KEY_FIRST_ACCOUNT_ID = "onboarding_first_added_account_id"
+    }
 }
diff --git a/app/src/main/kotlin/org/libremail/ui/reader/ReaderScreen.kt b/app/src/main/kotlin/org/libremail/ui/reader/ReaderScreen.kt
index a53d204..d962968 100644
--- a/app/src/main/kotlin/org/libremail/ui/reader/ReaderScreen.kt
+++ b/app/src/main/kotlin/org/libremail/ui/reader/ReaderScreen.kt
@@ -85,6 +85,7 @@ fun ReaderScreen(
     val noAppMessage = stringResource(R.string.attachment_no_app)
     val downloadFailedTemplate = stringResource(R.string.attachment_download_failed)
     val replyFailedMessage = stringResource(R.string.reader_reply_failed)
+    val starFailedMessage = stringResource(R.string.reader_star_failed)
 
     LaunchedEffect(state.deleted) {
         if (state.deleted) onBack()
@@ -105,6 +106,8 @@ fun ReaderScreen(
 
                 is ReaderEvent.ComposeFailed ->
                     snackbarHostState.showSnackbar(event.message ?: replyFailedMessage)
+
+                ReaderEvent.StarFailed -> snackbarHostState.showSnackbar(starFailedMessage)
             }
         }
     }
diff --git a/app/src/main/kotlin/org/libremail/ui/reader/ReaderViewModel.kt b/app/src/main/kotlin/org/libremail/ui/reader/ReaderViewModel.kt
index 01b1e2e..0ac70d7 100644
--- a/app/src/main/kotlin/org/libremail/ui/reader/ReaderViewModel.kt
+++ b/app/src/main/kotlin/org/libremail/ui/reader/ReaderViewModel.kt
@@ -50,6 +50,9 @@ sealed interface ReaderEvent {
 
     /** Building the reply/forward draft failed; the screen surfaces [message] (or a generic fallback). */
     data class ComposeFailed(val message: String?) : ReaderEvent
+
+    /** Persisting a star toggle failed; the optimistic flip was rolled back and the screen notifies. */
+    data object StarFailed : ReaderEvent
 }
 
 @HiltViewModel
@@ -140,7 +143,19 @@ class ReaderViewModel @Inject constructor(
         val message = _state.value.message ?: return
         val starred = !message.isStarred
         _state.update { it.copy(message = message.copy(isStarred = starred)) }
-        viewModelScope.launch { repository.setStarred(messageId, starred) }
+        viewModelScope.launch {
+            repository.setStarred(messageId, starred).onFailure { e ->
+                // The optimistic flip already updated the UI; the persist failed, so reconcile by rolling
+                // it back (the star would otherwise stay stuck in a state the store never accepted) and
+                // notify the screen. Revert to the pre-toggle value (!starred) of the current message.
+                AppLog.w(READER_TAG, "toggleStar persist failed; rolling back optimistic star", e)
+                _state.update { current ->
+                    val shown = current.message ?: return@update current
+                    current.copy(message = shown.copy(isStarred = !starred))
+                }
+                _events.send(ReaderEvent.StarFailed)
+            }
+        }
     }
 
     fun loadRemoteImages() = _state.update { it.copy(loadRemoteImages = true) }
diff --git a/app/src/main/kotlin/org/libremail/ui/settings/SettingsViewModel.kt b/app/src/main/kotlin/org/libremail/ui/settings/SettingsViewModel.kt
index 7ac058b..33a47ea 100644
--- a/app/src/main/kotlin/org/libremail/ui/settings/SettingsViewModel.kt
+++ b/app/src/main/kotlin/org/libremail/ui/settings/SettingsViewModel.kt
@@ -2,9 +2,12 @@
 package org.libremail.ui.settings
 
 import android.content.Intent
+import androidx.annotation.VisibleForTesting
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import dagger.hilt.android.lifecycle.HiltViewModel
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
@@ -12,6 +15,7 @@ import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
 import org.libremail.R
 import org.libremail.contacts.ContactsPermissionManager
 import org.libremail.data.security.AppLockManager
@@ -62,6 +66,12 @@ class SettingsViewModel @Inject constructor(
     /** Whether this app is exempt from battery optimization ("Unrestricted"). */
     val batteryUnrestricted: StateFlow<Boolean> = _batteryUnrestricted.asStateFlow()
 
+    // Blocking Keystore/DataStore work on the app-lock disable path runs here — off the main
+    // dispatcher — mirroring AppLockViewModel's threading policy so the reseal never runs Keystore
+    // crypto on the main thread (#308). Injectable so unit tests can pin it to their scheduler.
+    @VisibleForTesting
+    internal var defaultDispatcher: CoroutineDispatcher = Dispatchers.Default
+
     fun toggleAdvanced() = _advancedExpanded.update { !it }
 
     /** Persist the account order the user produced by dragging in Settings (issue #164). */
@@ -110,13 +120,19 @@ class SettingsViewModel @Inject constructor(
             // Reseal under the master key whenever an auth seal actually exists — gate on the seal, not
             // the encryptCache setting (a separate store that can already be off while the on-disk DB is
             // still auth-sealed). Do it BEFORE dropping the gate, or the next launch can't open the
-            // cache. If it fails, keep app-lock on rather than strand the passphrase.
-            if (databaseKeyStore.hasAuthSealedPassphrase()) {
-                if (runCatching { databaseKeyStore.sealWithMaster() }.isFailure) {
-                    _appLockMessage.value = R.string.app_lock_disable_failed
-                    return@update
+            // cache. If it fails, keep app-lock on rather than strand the passphrase. The Keystore/
+            // DataStore reseal is blocking crypto, so it runs off the main thread (#308).
+            val resealed = withContext(defaultDispatcher) {
+                if (databaseKeyStore.hasAuthSealedPassphrase()) {
+                    runCatching { databaseKeyStore.sealWithMaster() }.isSuccess
+                } else {
+                    true
                 }
             }
+            if (!resealed) {
+                _appLockMessage.value = R.string.app_lock_disable_failed
+                return@update
+            }
             settingsRepository.setAppLock(false)
         }
     }
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 8c6b86a..4fd05e4 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -151,6 +151,7 @@
     <!-- Reader -->
     <string name="reader_reply">Reply</string>
     <string name="reader_reply_failed">Couldn\'t start the reply</string>
+    <string name="reader_star_failed">Couldn\'t update star</string>
     <string name="attachments_title">Attachments</string>
     <string name="attachment_downloaded">Downloaded</string>
     <string name="message_available_offline">Available offline</string>
diff --git a/app/src/test/kotlin/org/libremail/ui/accountsetup/AccountSetupViewModelTest.kt b/app/src/test/kotlin/org/libremail/ui/accountsetup/AccountSetupViewModelTest.kt
index 332bf07..8ff4571 100644
--- a/app/src/test/kotlin/org/libremail/ui/accountsetup/AccountSetupViewModelTest.kt
+++ b/app/src/test/kotlin/org/libremail/ui/accountsetup/AccountSetupViewModelTest.kt
@@ -124,13 +124,18 @@ class AccountSetupViewModelTest {
     }
 
     @Test
-    fun `a cancelled sign-in (null result) surfaces a cancellation message`() {
+    fun `a cancelled sign-in (null result) is a no-op, not an error`() {
         val vm = viewModel()
 
         vm.onOutlookResult(null)
 
-        assertEquals("Microsoft sign-in was cancelled", vm.state.value.error)
+        // #308: a normal cancel (backing out of the sign-in tab → RESULT_CANCELED, null data) must not
+        // raise an error snackbar; it leaves the screen untouched (idle, no error) and only breadcrumbs.
+        assertNull(vm.state.value.error)
         assertEquals(SetupStatus.IDLE, vm.state.value.status)
+        val entry = logBuffer.snapshot().single()
+        assertEquals('D', entry.level)
+        assertTrue(entry.message.contains("cancelled"), entry.message)
     }
 
     @Test
@@ -263,7 +268,9 @@ class AccountSetupViewModelTest {
     @Test
     fun `consumeError clears a surfaced error`() {
         val vm = viewModel()
-        vm.onOutlookResult(null)
+        // Surface a real error first (a cancel is now a no-op), then confirm consumeError clears it.
+        vm.onOutlookLaunchFailed(IllegalStateException("appauth exploded"))
+        assertEquals("appauth exploded", vm.state.value.error)
 
         vm.consumeError()
 
diff --git a/app/src/test/kotlin/org/libremail/ui/compose/RichTextEditorTest.kt b/app/src/test/kotlin/org/libremail/ui/compose/RichTextEditorTest.kt
index 3746d0c..8b033bb 100644
--- a/app/src/test/kotlin/org/libremail/ui/compose/RichTextEditorTest.kt
+++ b/app/src/test/kotlin/org/libremail/ui/compose/RichTextEditorTest.kt
@@ -348,6 +348,37 @@ class RichTextEditorTest {
         assertTrue(isBulletActive(bothLines.copy(selection = fullText)))
     }
 
+    @Test
+    fun `toolbarStateOf derives every button's state from the field value in a single pass`() {
+        // A run carrying bold + color + size, centered, on a bullet line. applyBlock inserts "• " and
+        // lands the selection back on the styled text, so every scan sees the same run the user is on.
+        var value = field("hello", TextRange(0, 5))
+        value = applyStyle(value, RichStyle.Bold, linkColor)
+        value = applyStyle(value, RichStyle.FontColor(0xFF112233.toInt()), linkColor)
+        value = applyStyle(value, RichStyle.FontSize(18), linkColor)
+        value = applyAlignment(value, RichAlign.CENTER, linkColor, noFont)
+        value = applyBlock(value, BlockMarker.BULLET, linkColor, noFont)
+
+        val state = toolbarStateOf(value)
+
+        assertTrue(state.bold)
+        assertFalse(state.italic)
+        assertFalse(state.underline)
+        assertFalse(state.strikethrough)
+        assertEquals(0xFF112233.toInt(), state.fontColorArgb)
+        assertEquals(null, state.highlightArgb)
+        assertEquals(18, state.fontSizePt)
+        assertEquals(null, state.fontCss)
+        assertTrue(state.bullet)
+        assertFalse(state.ordered)
+        assertFalse(state.quote)
+        assertEquals(RichAlign.CENTER, state.alignment)
+        // Each field equals reading the same predicate directly off the value: the memoization the
+        // toolbar wraps this in (remember(value)) is behaviour-preserving, just computed once (#308).
+        assertEquals(isBoldActive(value), state.bold)
+        assertEquals(isBulletActive(value), state.bullet)
+    }
+
     /** Mirrors exactly what FormattingToolbar reads to decide a style button's active/inactive tint. */
     private fun isBoldActive(value: TextFieldValue): Boolean = RichTextEditing.isStyled(
         value.annotatedString.toRichContent(),
diff --git a/app/src/test/kotlin/org/libremail/ui/lock/AppLockGateHostJvmTest.kt b/app/src/test/kotlin/org/libremail/ui/lock/AppLockGateHostJvmTest.kt
index 3072a57..c27d0ff 100644
--- a/app/src/test/kotlin/org/libremail/ui/lock/AppLockGateHostJvmTest.kt
+++ b/app/src/test/kotlin/org/libremail/ui/lock/AppLockGateHostJvmTest.kt
@@ -4,6 +4,7 @@ package org.libremail.ui.lock
 import android.content.Context
 import androidx.compose.material3.Text
 import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.runtime.DisposableEffect
 import androidx.compose.ui.test.assertIsDisplayed
 import androidx.compose.ui.test.junit4.v2.createComposeRule
 import androidx.compose.ui.test.onNodeWithText
@@ -24,6 +25,7 @@ import org.robolectric.RobolectricTestRunner
 import org.robolectric.RuntimeEnvironment
 import org.robolectric.annotation.Config
 import org.robolectric.annotation.GraphicsMode
+import kotlin.test.assertEquals
 
 /**
  * Robolectric JVM Compose test (#384, umbrella #373) for [AppLockGateHost], the gate that wraps the
@@ -109,26 +111,50 @@ class AppLockGateHostJvmTest {
     }
 
     @Test
-    fun reLockAfterUnlock_drawsLockScreenButKeepsContentComposed() {
+    fun reLockAfterUnlock_keepsContentComposedButGatesItOutOfTheAccessibilityTree() {
         val state = MutableStateFlow<AppLockUiState>(AppLockUiState.Unlocked)
         val vm = mockk<AppLockViewModel>(relaxed = true)
         every { vm.uiState } returns state
+        // Track the content's composition lifecycle directly: entered once and never disposed proves the
+        // content composable is RETAINED across a re-lock (its nav/scroll/draft state survives) rather
+        // than torn down — independently of whether its semantics are currently in the tree.
+        var entered = 0
+        var disposed = 0
         composeTestRule.setContent {
             CompositionLocalProvider(LocalLifecycleOwner provides resumedOwner) {
                 LibreMailTheme(darkTheme = false, dynamicColor = false) {
-                    AppLockGateHost(viewModel = vm) { Text(CONTENT) }
+                    AppLockGateHost(viewModel = vm) {
+                        DisposableEffect(Unit) {
+                            entered++
+                            onDispose { disposed++ }
+                        }
+                        Text(CONTENT)
+                    }
                 }
             }
         }
         composeTestRule.onNodeWithText(CONTENT).assertIsDisplayed()
+        assertEquals(1, entered)
 
-        // Re-lock: once ever unlocked, the content stays composed (its nav/scroll/draft state survives)
-        // and the lock screen is drawn OVER it rather than replacing it.
+        // Re-lock: the lock screen is drawn OVER the content. The content stays composed (entered==1,
+        // never disposed), but #308 clears it out of the semantics/accessibility tree so TalkBack can't
+        // traverse the occluded mailbox nodes behind the opaque cover — assertDoesNotExist confirms the
+        // content's text is no longer reachable in the (a11y-facing) semantics tree.
         state.value = AppLockUiState.Locked()
         composeTestRule.waitForIdle()
 
         composeTestRule.onNodeWithText(string(R.string.app_lock_title)).assertIsDisplayed()
-        composeTestRule.onNodeWithText(CONTENT).assertExists()
+        composeTestRule.onNodeWithText(CONTENT).assertDoesNotExist()
+        assertEquals(1, entered)
+        assertEquals(0, disposed)
+
+        // Unlocking again restores the content's semantics (same retained composition — still one entry).
+        state.value = AppLockUiState.Unlocked
+        composeTestRule.waitForIdle()
+
+        composeTestRule.onNodeWithText(CONTENT).assertIsDisplayed()
+        assertEquals(1, entered)
+        assertEquals(0, disposed)
     }
 
     private companion object {
diff --git a/app/src/test/kotlin/org/libremail/ui/onboarding/OnboardingViewModelTest.kt b/app/src/test/kotlin/org/libremail/ui/onboarding/OnboardingViewModelTest.kt
index 2228d51..ac9cf95 100644
--- a/app/src/test/kotlin/org/libremail/ui/onboarding/OnboardingViewModelTest.kt
+++ b/app/src/test/kotlin/org/libremail/ui/onboarding/OnboardingViewModelTest.kt
@@ -1,12 +1,16 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 package org.libremail.ui.onboarding
 
+import android.util.Log
+import androidx.lifecycle.SavedStateHandle
 import io.mockk.Runs
 import io.mockk.coEvery
 import io.mockk.coVerify
 import io.mockk.every
 import io.mockk.just
 import io.mockk.mockk
+import io.mockk.mockkStatic
+import io.mockk.unmockkAll
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.test.UnconfinedTestDispatcher
@@ -30,10 +34,19 @@ class OnboardingViewModelTest {
     private val testDispatcher = UnconfinedTestDispatcher()
 
     @Before
-    fun setUp() = Dispatchers.setMain(testDispatcher)
+    fun setUp() {
+        Dispatchers.setMain(testDispatcher)
+        // onAccountAdded now breadcrumbs the first account via AppLog (#308); android.util.Log is a
+        // no-op stub that throws "not mocked" under plain JVM tests, so stub it so the call can't crash.
+        mockkStatic(Log::class)
+        every { Log.i(any(), any()) } returns 0
+    }
 
     @After
-    fun tearDown() = Dispatchers.resetMain()
+    fun tearDown() {
+        Dispatchers.resetMain()
+        unmockkAll()
+    }
 
     private fun batteryManager(supported: Boolean = true, unrestricted: Boolean = false) =
         mockk<BatteryOptimizationManager> {
@@ -55,7 +68,8 @@ class OnboardingViewModelTest {
         battery: BatteryOptimizationManager = batteryManager(),
         contacts: ContactsPermissionManager = contactsManager(),
         settings: SettingsRepository = settingsRepository(),
-    ) = OnboardingViewModel(battery, contacts, settings)
+        savedStateHandle: SavedStateHandle = SavedStateHandle(),
+    ) = OnboardingViewModel(battery, contacts, settings, savedStateHandle)
 
     @Test
     fun `battery prompt is needed when not unrestricted and not handled`() = runTest(testDispatcher) {
@@ -123,6 +137,21 @@ class OnboardingViewModelTest {
         assertEquals("imap:first@example.com", vm.firstAddedAccountId)
     }
 
+    @Test
+    fun `the first added account id survives a process-death recreation via SavedStateHandle`() =
+        runTest(testDispatcher) {
+            // #308: onboarding can be process-killed mid-flow (e.g. the excursion to system battery
+            // settings). The first-account id lives in SavedStateHandle, so a recreated ViewModel over
+            // the restored state must still finish onto that account's inbox rather than the unified one.
+            val handle = SavedStateHandle()
+            viewModel(savedStateHandle = handle).onAccountAdded("imap:first@example.com")
+
+            // Simulate restoration after a kill: a brand-new handle seeded from the saved state, then a
+            // fresh ViewModel over it (a plain field would have been lost — this is exactly #30's guard).
+            val restored = SavedStateHandle(handle.keys().associateWith { handle.get<Any?>(it) })
+            assertEquals("imap:first@example.com", viewModel(savedStateHandle = restored).firstAddedAccountId)
+        }
+
     @Test
     fun `marking the battery prompt handled persists the flag`() = runTest(testDispatcher) {
         val repo = settingsRepository()
diff --git a/app/src/test/kotlin/org/libremail/ui/reader/ReaderViewModelActionsTest.kt b/app/src/test/kotlin/org/libremail/ui/reader/ReaderViewModelActionsTest.kt
index c64bc30..503a825 100644
--- a/app/src/test/kotlin/org/libremail/ui/reader/ReaderViewModelActionsTest.kt
+++ b/app/src/test/kotlin/org/libremail/ui/reader/ReaderViewModelActionsTest.kt
@@ -55,6 +55,9 @@ class ReaderViewModelActionsTest {
         every { Log.d(any(), any()) } returns 0
         every { Log.i(any(), any()) } returns 0
         every { Log.w(any<String>(), any<String>()) } returns 0
+        // toggleStar's rollback path logs via AppLog.w(tag, msg, throwable) -> Log.w(String, String,
+        // Throwable); stub that overload too so the failing-write test's coroutine doesn't crash on it.
+        every { Log.w(any<String>(), any<String>(), any()) } returns 0
         every { Log.e(any(), any(), any()) } returns 0
     }
 
@@ -78,6 +81,7 @@ class ReaderViewModelActionsTest {
         coEvery { repo.openMessage(messageId) } returns Result.success(message)
         every { repo.observeAttachments(messageId) } returns flowOf(listOf(attachment(0)))
         coEvery { repo.downloadedAttachmentParts(messageId) } returns emptySet()
+        coEvery { repo.setStarred(any(), any()) } returns Result.success(Unit)
         return repo
     }
 
@@ -181,6 +185,28 @@ class ReaderViewModelActionsTest {
         coVerify { repo.setStarred(messageId, true) }
     }
 
+    @Test
+    fun `toggleStar rolls the optimistic star back and emits StarFailed when the write fails`() = runTest(dispatcher) {
+        val repo = loadedRepo()
+        coEvery { repo.setStarred(messageId, true) } returns Result.failure(RuntimeException("db locked"))
+        val vm = viewModel(repo)
+        advanceUntilIdle()
+        assertFalse(vm.state.value.message!!.isStarred)
+
+        vm.events.test {
+            vm.toggleStar()
+            // The optimistic flip lands immediately, before the (failing) persist runs.
+            assertTrue(vm.state.value.message!!.isStarred)
+            advanceUntilIdle()
+
+            assertEquals(ReaderEvent.StarFailed, awaitItem())
+            // The failed write is reconciled: the star is rolled back to its pre-toggle value so the
+            // UI never stays stuck in a state the store rejected.
+            assertFalse(vm.state.value.message!!.isStarred)
+            cancelAndIgnoreRemainingEvents()
+        }
+    }
+
     @Test
     fun `toggleStar does nothing before the message has loaded`() = runTest(dispatcher) {
         val repo = mockk<MailRepository>(relaxed = true)
diff --git a/app/src/test/kotlin/org/libremail/ui/settings/SettingsViewModelTest.kt b/app/src/test/kotlin/org/libremail/ui/settings/SettingsViewModelTest.kt
index 00e50c6..cec7e02 100644
--- a/app/src/test/kotlin/org/libremail/ui/settings/SettingsViewModelTest.kt
+++ b/app/src/test/kotlin/org/libremail/ui/settings/SettingsViewModelTest.kt
@@ -9,6 +9,7 @@ import io.mockk.mockk
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.flow.flowOf
+import kotlinx.coroutines.test.StandardTestDispatcher
 import kotlinx.coroutines.test.UnconfinedTestDispatcher
 import kotlinx.coroutines.test.advanceUntilIdle
 import kotlinx.coroutines.test.resetMain
@@ -107,6 +108,26 @@ class SettingsViewModelTest {
         coVerify(exactly = 0) { settingsRepository.setAppLock(false) }
     }
 
+    @Test
+    fun `the disable-path reseal is dispatched off the main thread, not run inline on main`() = runTest(dispatcher) {
+        val databaseKeyStore = mockk<DatabaseKeyStore>(relaxed = true)
+        coEvery { databaseKeyStore.hasAuthSealedPassphrase() } returns true
+        val settingsRepository = mockk<SettingsRepository>(relaxed = true)
+        val vm = viewModel(databaseKeyStore = databaseKeyStore, settingsRepository = settingsRepository)
+        // Swap the pinned dispatcher for a queue-and-drain one (sharing the scheduler) so we can see
+        // that the blocking Keystore reseal is DISPATCHED off-main rather than run inline on Main's
+        // unconfined pass — the point of #308: no Keystore crypto on the main dispatcher.
+        vm.defaultDispatcher = StandardTestDispatcher(testScheduler)
+
+        vm.setAppLock(false)
+
+        // Dispatched to defaultDispatcher, so it has not run on the current (unconfined Main) pass...
+        coVerify(exactly = 0) { databaseKeyStore.sealWithMaster() }
+        advanceUntilIdle()
+        // ...only once that off-main dispatcher is drained.
+        coVerify(exactly = 1) { databaseKeyStore.sealWithMaster() }
+    }
+
     @Test
     fun `disabling app-lock with no auth seal just drops the gate`() = runTest(dispatcher) {
         val databaseKeyStore = mockk<DatabaseKeyStore>(relaxed = true)
@@ -139,6 +160,10 @@ class SettingsViewModelTest {
             batteryOptimizationManager = mockk(relaxed = true),
             contactsPermissionManager = mockk(relaxed = true),
             syncScheduler = mockk(relaxed = true),
-        )
+        ).apply {
+            // Pin the off-main reseal dispatcher (#308) to the test scheduler so the disable path's
+            // withContext(defaultDispatcher) work is advanced deterministically by advanceUntilIdle().
+            defaultDispatcher = dispatcher
+        }
     }
 }
diff --git a/config/detekt/detekt.yml b/config/detekt/detekt.yml
index f190f3c..2cbbe1f 100644
--- a/config/detekt/detekt.yml
+++ b/config/detekt/detekt.yml
@@ -79,6 +79,9 @@ style:
       - '**/data/repository/AccountRepositoryImplTest.kt'
       - '**/ui/reader/ReaderViewModelTest.kt'
       - '**/ui/reader/ReaderViewModelActionsTest.kt'
+      # First-account onboarding breadcrumb (issue #308): onAccountAdded logs via AppLog, so this
+      # suite mockkStatic(Log) so the call doesn't crash on the throwing JVM stub.
+      - '**/ui/onboarding/OnboardingViewModelTest.kt'
   MagicNumber:
     # dp / sp / duration literals are idiomatic inline in Compose.
     ignoreAnnotated: ['Composable']