diff --git a/app/src/main/java/org/thoughtcrime/securesms/linkdevice/EditDeviceNameFragment.kt b/app/src/main/java/org/thoughtcrime/securesms/linkdevice/EditDeviceNameFragment.kt
index 7bae8b4053..d56977ac8b 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/linkdevice/EditDeviceNameFragment.kt
+++ b/app/src/main/java/org/thoughtcrime/securesms/linkdevice/EditDeviceNameFragment.kt
@@ -75,6 +75,7 @@ class EditDeviceNameFragment : ComposeFragment() {
         is LinkDeviceSettingsState.OneTimeEvent.ToastLinked -> Unit
         LinkDeviceSettingsState.OneTimeEvent.ToastNetworkFailed -> Unit
         is LinkDeviceSettingsState.OneTimeEvent.ToastUnlinked -> Unit
+        LinkDeviceSettingsState.OneTimeEvent.SnackbarLinkCancelled -> Unit
       }
     }
 
diff --git a/app/src/main/java/org/thoughtcrime/securesms/linkdevice/LinkDeviceFragment.kt b/app/src/main/java/org/thoughtcrime/securesms/linkdevice/LinkDeviceFragment.kt
index b9e41f3164..c1da10c389 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/linkdevice/LinkDeviceFragment.kt
+++ b/app/src/main/java/org/thoughtcrime/securesms/linkdevice/LinkDeviceFragment.kt
@@ -57,6 +57,7 @@ import androidx.fragment.app.activityViewModels
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.navigation.NavController
 import androidx.navigation.fragment.findNavController
+import com.google.android.material.snackbar.Snackbar
 import org.signal.core.ui.Buttons
 import org.signal.core.ui.Dialogs
 import org.signal.core.ui.Dividers
@@ -132,7 +133,7 @@ class LinkDeviceFragment : ComposeFragment() {
           Log.i(TAG, "Releasing wake lock for linked device")
           linkDeviceWakeLock.release()
         }
-        DialogState.SyncingMessages, DialogState.Linking -> {
+        is DialogState.SyncingMessages, DialogState.Linking -> {
           Log.i(TAG, "Acquiring wake lock for linked device")
           linkDeviceWakeLock.acquire()
         }
@@ -151,6 +152,9 @@ class LinkDeviceFragment : ComposeFragment() {
         is LinkDeviceSettingsState.OneTimeEvent.ToastUnlinked -> {
           Toast.makeText(context, context.getString(R.string.LinkDeviceFragment__s_unlinked, event.name), Toast.LENGTH_LONG).show()
         }
+        LinkDeviceSettingsState.OneTimeEvent.SnackbarLinkCancelled -> {
+          Snackbar.make(requireView(), context.getString(R.string.LinkDeviceFragment__linking_cancelled), Snackbar.LENGTH_LONG).show()
+        }
         LinkDeviceSettingsState.OneTimeEvent.ToastNetworkFailed -> {
           Toast.makeText(context, context.getString(R.string.DeviceListActivity_network_failed), Toast.LENGTH_LONG).show()
         }
@@ -198,6 +202,7 @@ class LinkDeviceFragment : ComposeFragment() {
         onDeviceRemovalConfirmed = { device -> viewModel.removeDevice(device) },
         onSyncFailureRetryRequested = { viewModel.onSyncErrorRetryRequested() },
         onSyncFailureIgnored = { viewModel.onSyncErrorIgnored() },
+        onSyncCancelled = { viewModel.onSyncCancelled() },
         onEditDevice = { device ->
           viewModel.setDeviceToEdit(device)
           navController.safeNavigate(R.id.action_linkDeviceFragment_to_editDeviceNameFragment)
@@ -251,6 +256,7 @@ fun DeviceListScreen(
   onDeviceRemovalConfirmed: (Device) -> Unit = {},
   onSyncFailureRetryRequested: () -> Unit = {},
   onSyncFailureIgnored: () -> Unit = {},
+  onSyncCancelled: () -> Unit = {},
   onEditDevice: (Device) -> Unit = {}
 ) {
   // If a bottom sheet is showing, we don't want the spinner underneath
@@ -265,8 +271,13 @@ fun DeviceListScreen(
       DialogState.Unlinking -> {
         Dialogs.IndeterminateProgressDialog(stringResource(id = R.string.DeviceListActivity_unlinking_device))
       }
-      DialogState.SyncingMessages -> {
-        Dialogs.IndeterminateProgressDialog(stringResource(id = R.string.LinkDeviceFragment__syncing_messages))
+      is DialogState.SyncingMessages -> {
+        Dialogs.IndeterminateProgressDialog(
+          message = stringResource(id = R.string.LinkDeviceFragment__syncing_messages),
+          caption = stringResource(id = R.string.LinkDeviceFragment__do_not_close),
+          dismiss = stringResource(id = android.R.string.cancel),
+          onDismiss = onSyncCancelled
+        )
       }
       is DialogState.SyncingFailed,
       DialogState.SyncingTimedOut -> {
@@ -507,7 +518,9 @@ private fun DeviceListScreenPreview() {
         devices = listOf(
           Device(1, "Sam's Macbook Pro", 1715793982000, 1716053182000),
           Device(1, "Sam's iPad", 1715793182000, 1716053122000)
-        )
+        ),
+        seenQrEducationSheet = true,
+        seenBioAuthEducationSheet = true
       )
     )
   }
@@ -519,7 +532,9 @@ private fun DeviceListScreenLoadingPreview() {
   Previews.Preview {
     DeviceListScreen(
       state = LinkDeviceSettingsState(
-        deviceListLoading = true
+        deviceListLoading = true,
+        seenQrEducationSheet = true,
+        seenBioAuthEducationSheet = true
       )
     )
   }
@@ -531,7 +546,9 @@ private fun DeviceListScreenLinkingPreview() {
   Previews.Preview {
     DeviceListScreen(
       state = LinkDeviceSettingsState(
-        dialogState = DialogState.Linking
+        dialogState = DialogState.Linking,
+        seenQrEducationSheet = true,
+        seenBioAuthEducationSheet = true
       )
     )
   }
@@ -543,7 +560,9 @@ private fun DeviceListScreenUnlinkingPreview() {
   Previews.Preview {
     DeviceListScreen(
       state = LinkDeviceSettingsState(
-        dialogState = DialogState.Unlinking
+        dialogState = DialogState.Unlinking,
+        seenQrEducationSheet = true,
+        seenBioAuthEducationSheet = true
       )
     )
   }
@@ -555,7 +574,9 @@ private fun DeviceListScreenSyncingMessagesPreview() {
   Previews.Preview {
     DeviceListScreen(
       state = LinkDeviceSettingsState(
-        dialogState = DialogState.SyncingMessages
+        dialogState = DialogState.SyncingMessages(1, 1),
+        seenQrEducationSheet = true,
+        seenBioAuthEducationSheet = true
       )
     )
   }
@@ -567,7 +588,9 @@ private fun DeviceListScreenSyncingFailedPreview() {
   Previews.Preview {
     DeviceListScreen(
       state = LinkDeviceSettingsState(
-        dialogState = DialogState.SyncingTimedOut
+        dialogState = DialogState.SyncingTimedOut,
+        seenQrEducationSheet = true,
+        seenBioAuthEducationSheet = true
       )
     )
   }
diff --git a/app/src/main/java/org/thoughtcrime/securesms/linkdevice/LinkDeviceRepository.kt b/app/src/main/java/org/thoughtcrime/securesms/linkdevice/LinkDeviceRepository.kt
index 3428af33e9..fe68def73e 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/linkdevice/LinkDeviceRepository.kt
+++ b/app/src/main/java/org/thoughtcrime/securesms/linkdevice/LinkDeviceRepository.kt
@@ -241,7 +241,7 @@ object LinkDeviceRepository {
   /**
    * Performs the entire process of creating and uploading an archive for a newly-linked device.
    */
-  fun createAndUploadArchive(ephemeralMessageBackupKey: MessageBackupKey, deviceId: Int, deviceCreatedAt: Long): LinkUploadArchiveResult {
+  fun createAndUploadArchive(ephemeralMessageBackupKey: MessageBackupKey, deviceId: Int, deviceCreatedAt: Long, cancellationSignal: () -> Boolean): LinkUploadArchiveResult {
     Log.d(TAG, "[createAndUploadArchive] Beginning process.")
     val stopwatch = Stopwatch("link-archive")
     val tempBackupFile = BlobProvider.getInstance().forNonAutoEncryptingSingleSessionOnDisk(AppDependencies.application)
@@ -249,7 +249,13 @@ object LinkDeviceRepository {
 
     try {
       Log.d(TAG, "[createAndUploadArchive] Starting the export.")
-      BackupRepository.export(outputStream = outputStream, append = { tempBackupFile.appendBytes(it) }, messageBackupKey = ephemeralMessageBackupKey, mediaBackupEnabled = false)
+      BackupRepository.export(
+        outputStream = outputStream,
+        append = { tempBackupFile.appendBytes(it) },
+        messageBackupKey = ephemeralMessageBackupKey,
+        mediaBackupEnabled = false,
+        cancellationSignal = cancellationSignal
+      )
     } catch (e: Exception) {
       Log.w(TAG, "[createAndUploadArchive] Failed to export a backup!", e)
       return LinkUploadArchiveResult.BackupCreationFailure(e)
@@ -257,6 +263,11 @@ object LinkDeviceRepository {
     Log.d(TAG, "[createAndUploadArchive] Successfully created backup.")
     stopwatch.split("create-backup")
 
+    if (cancellationSignal()) {
+      Log.i(TAG, "[createAndUploadArchive] Backup was cancelled.")
+      return LinkUploadArchiveResult.BackupCreationCancelled
+    }
+
     when (val result = ArchiveValidator.validate(tempBackupFile, ephemeralMessageBackupKey)) {
       ArchiveValidator.ValidationResult.Success -> {
         Log.d(TAG, "[createAndUploadArchive] Successfully passed validation.")
@@ -272,6 +283,11 @@ object LinkDeviceRepository {
     }
     stopwatch.split("validate-backup")
 
+    if (cancellationSignal()) {
+      Log.i(TAG, "[createAndUploadArchive] Backup was cancelled.")
+      return LinkUploadArchiveResult.BackupCreationCancelled
+    }
+
     Log.d(TAG, "[createAndUploadArchive] Fetching an upload form...")
     val uploadForm = when (val result = NetworkResult.withRetry { SignalNetwork.attachments.getAttachmentV4UploadForm() }) {
       is NetworkResult.Success -> result.result.logD(TAG, "[createAndUploadArchive] Successfully retrieved upload form.")
@@ -280,6 +296,11 @@ object LinkDeviceRepository {
       is NetworkResult.StatusCodeError -> return LinkUploadArchiveResult.NetworkError(result.exception).logW(TAG, "[createAndUploadArchive] Status code error when fetching form.", result.exception)
     }
 
+    if (cancellationSignal()) {
+      Log.i(TAG, "[createAndUploadArchive] Backup was cancelled.")
+      return LinkUploadArchiveResult.BackupCreationCancelled
+    }
+
     when (val result = uploadArchive(tempBackupFile, uploadForm)) {
       is NetworkResult.Success -> Log.i(TAG, "[createAndUploadArchive] Successfully uploaded backup.")
       is NetworkResult.NetworkError -> return LinkUploadArchiveResult.NetworkError(result.exception).logW(TAG, "[createAndUploadArchive] Network error when uploading archive.", result.exception)
@@ -288,6 +309,11 @@ object LinkDeviceRepository {
     }
     stopwatch.split("upload-backup")
 
+    if (cancellationSignal()) {
+      Log.i(TAG, "[createAndUploadArchive] Backup was cancelled.")
+      return LinkUploadArchiveResult.BackupCreationCancelled
+    }
+
     Log.d(TAG, "[createAndUploadArchive] Setting the transfer archive...")
     val transferSetResult = NetworkResult.withRetry {
       SignalNetwork.linkDevice.setTransferArchive(
@@ -399,6 +425,7 @@ object LinkDeviceRepository {
 
   sealed interface LinkUploadArchiveResult {
     data object Success : LinkUploadArchiveResult
+    data object BackupCreationCancelled : LinkUploadArchiveResult
     data class BackupCreationFailure(val exception: Exception) : LinkUploadArchiveResult
     data class BadRequest(val exception: IOException) : LinkUploadArchiveResult
     data class NetworkError(val exception: IOException) : LinkUploadArchiveResult
diff --git a/app/src/main/java/org/thoughtcrime/securesms/linkdevice/LinkDeviceSettingsState.kt b/app/src/main/java/org/thoughtcrime/securesms/linkdevice/LinkDeviceSettingsState.kt
index ecbf53a91c..53b17ad968 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/linkdevice/LinkDeviceSettingsState.kt
+++ b/app/src/main/java/org/thoughtcrime/securesms/linkdevice/LinkDeviceSettingsState.kt
@@ -21,13 +21,14 @@ data class LinkDeviceSettingsState(
   val seenBioAuthEducationSheet: Boolean = false,
   val needsBioAuthEducationSheet: Boolean = !seenBioAuthEducationSheet && !SignalStore.uiHints.hasSeenLinkDeviceAuthSheet() && !SignalStore.account.hasLinkedDevices,
   val bottomSheetVisible: Boolean = false,
-  val deviceToEdit: Device? = null
+  val deviceToEdit: Device? = null,
+  val shouldCancelArchiveUpload: Boolean = false
 ) {
   sealed interface DialogState {
     data object None : DialogState
     data object Linking : DialogState
     data object Unlinking : DialogState
-    data object SyncingMessages : DialogState
+    data class SyncingMessages(val deviceId: Int, val deviceCreatedAt: Long) : DialogState
     data object SyncingTimedOut : DialogState
     data class SyncingFailed(val deviceId: Int, val deviceCreatedAt: Long) : DialogState
   }
@@ -37,6 +38,7 @@ data class LinkDeviceSettingsState(
     data object ToastNetworkFailed : OneTimeEvent
     data class ToastUnlinked(val name: String) : OneTimeEvent
     data class ToastLinked(val name: String) : OneTimeEvent
+    data object SnackbarLinkCancelled : OneTimeEvent
     data object SnackbarNameChangeSuccess : OneTimeEvent
     data object SnackbarNameChangeFailure : OneTimeEvent
     data object ShowFinishedSheet : OneTimeEvent
diff --git a/app/src/main/java/org/thoughtcrime/securesms/linkdevice/LinkDeviceViewModel.kt b/app/src/main/java/org/thoughtcrime/securesms/linkdevice/LinkDeviceViewModel.kt
index 50658bd80e..36b6bae685 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/linkdevice/LinkDeviceViewModel.kt
+++ b/app/src/main/java/org/thoughtcrime/securesms/linkdevice/LinkDeviceViewModel.kt
@@ -150,7 +150,8 @@ class LinkDeviceViewModel : ViewModel() {
       it.copy(
         qrCodeState = QrCodeState.NONE,
         linkUri = null,
-        dialogState = DialogState.Linking
+        dialogState = DialogState.Linking,
+        shouldCancelArchiveUpload = false
       )
     }
 
@@ -247,12 +248,17 @@ class LinkDeviceViewModel : ViewModel() {
     _state.update {
       it.copy(
         linkDeviceResult = result,
-        dialogState = DialogState.SyncingMessages
+        dialogState = DialogState.SyncingMessages(waitResult.id, waitResult.created)
       )
     }
 
     Log.d(TAG, "[addDeviceWithSync] Beginning the archive generation process...")
-    val uploadResult = LinkDeviceRepository.createAndUploadArchive(ephemeralMessageBackupKey, waitResult.id, waitResult.created)
+    val uploadResult = LinkDeviceRepository.createAndUploadArchive(
+      ephemeralMessageBackupKey = ephemeralMessageBackupKey,
+      deviceId = waitResult.id,
+      deviceCreatedAt = waitResult.created,
+      cancellationSignal = { _state.value.shouldCancelArchiveUpload }
+    )
 
     Log.d(TAG, "[addDeviceWithSync] Archive finished with result: $uploadResult")
     when (uploadResult) {
@@ -276,6 +282,14 @@ class LinkDeviceViewModel : ViewModel() {
           )
         }
       }
+      LinkDeviceRepository.LinkUploadArchiveResult.BackupCreationCancelled -> {
+        Log.i(TAG, "[addDeviceWithoutSync] Cancelling archive upload")
+        _state.update {
+          it.copy(
+            dialogState = DialogState.None
+          )
+        }
+      }
     }
   }
 
@@ -363,6 +377,26 @@ class LinkDeviceViewModel : ViewModel() {
     }
   }
 
+  fun onSyncCancelled() = viewModelScope.launch(Dispatchers.IO) {
+    Log.i(TAG, "Cancelling sync and removing linked device")
+    val dialogState = _state.value.dialogState
+    if (dialogState is DialogState.SyncingMessages) {
+      val success = LinkDeviceRepository.removeDevice(dialogState.deviceId)
+      if (success) {
+        Log.i(TAG, "Removing device after cancelling sync")
+        _state.update {
+          it.copy(
+            oneTimeEvent = OneTimeEvent.SnackbarLinkCancelled,
+            dialogState = DialogState.None,
+            shouldCancelArchiveUpload = true
+          )
+        }
+      } else {
+        Log.w(TAG, "Unable to remove device after cancelling sync")
+      }
+    }
+  }
+
   fun setDeviceToEdit(device: Device) {
     _state.update {
       it.copy(
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index d09c35acd0..d108d8b4fa 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -1016,6 +1016,10 @@
     <string name="LinkDeviceFragment__sync_failure_dismiss_button">Continue without transferring</string>
     <!-- Option in context menu to edit the name of a linked device -->
     <string name="LinkDeviceFragment__edit_name">Edit name</string>
+    <!-- Toast shown when the process of linking a device has been cancelled -->
+    <string name="LinkDeviceFragment__linking_cancelled">Linking cancelled</string>
+    <!-- Message shown in progress dialog telling users to avoid closing the app while messages are being synced -->
+    <string name="LinkDeviceFragment__do_not_close">Do not close app</string>
 
     <!-- EditDeviceNameFragment -->
     <!-- App bar title when editing the name of a device -->
diff --git a/core-ui/src/main/java/org/signal/core/ui/Dialogs.kt b/core-ui/src/main/java/org/signal/core/ui/Dialogs.kt
index 3bda3aee8b..d261fc660a 100644
--- a/core-ui/src/main/java/org/signal/core/ui/Dialogs.kt
+++ b/core-ui/src/main/java/org/signal/core/ui/Dialogs.kt
@@ -172,6 +172,52 @@ object Dialogs {
     )
   }
 
+  /**
+   * Customizable progress spinner that can be dismissed while showing [message]
+   * and [caption] below the spinner to let users know an action is completing
+   */
+  @Composable
+  fun IndeterminateProgressDialog(message: String, caption: String = "", dismiss: String, onDismiss: () -> Unit) {
+    androidx.compose.material3.AlertDialog(
+      onDismissRequest = {},
+      confirmButton = {},
+      dismissButton = {
+        TextButton(
+          onClick = onDismiss,
+          modifier = Modifier.fillMaxWidth(),
+          content = { Text(text = dismiss) }
+        )
+      },
+      text = {
+        Column(
+          verticalArrangement = Arrangement.Center,
+          horizontalAlignment = Alignment.CenterHorizontally,
+          modifier = Modifier.fillMaxWidth().fillMaxHeight()
+        ) {
+          Spacer(modifier = Modifier.size(32.dp))
+          CircularProgressIndicator()
+          Spacer(modifier = Modifier.size(12.dp))
+          Text(
+            text = message,
+            textAlign = TextAlign.Center,
+            style = MaterialTheme.typography.bodyMedium,
+            color = MaterialTheme.colorScheme.onSurface
+          )
+          if (caption.isNotEmpty()) {
+            Spacer(modifier = Modifier.size(8.dp))
+            Text(
+              text = caption,
+              textAlign = TextAlign.Center,
+              style = MaterialTheme.typography.bodySmall,
+              color = MaterialTheme.colorScheme.onSurfaceVariant
+            )
+          }
+        }
+      },
+      modifier = Modifier.size(200.dp, 250.dp)
+    )
+  }
+
   @OptIn(ExperimentalLayoutApi::class)
   @Composable
   fun PermissionRationaleDialog(
@@ -287,3 +333,9 @@ private fun IndeterminateProgressDialogPreview() {
 private fun IndeterminateProgressDialogMessagePreview() {
   Dialogs.IndeterminateProgressDialog("Completing...")
 }
+
+@Preview
+@Composable
+private fun IndeterminateProgressDialogCancellablePreview() {
+  Dialogs.IndeterminateProgressDialog("Completing...", "Do not close app", "Cancel") {}
+}