diff --git a/app/src/main/java/com/stevesoltys/seedvault/plugins/StoragePluginManager.kt b/app/src/main/java/com/stevesoltys/seedvault/plugins/StoragePluginManager.kt
index 509c0f5d..d4614e39 100644
--- a/app/src/main/java/com/stevesoltys/seedvault/plugins/StoragePluginManager.kt
+++ b/app/src/main/java/com/stevesoltys/seedvault/plugins/StoragePluginManager.kt
@@ -6,6 +6,7 @@
 package com.stevesoltys.seedvault.plugins
 
 import android.content.Context
+import android.util.Log
 import androidx.annotation.WorkerThread
 import com.stevesoltys.seedvault.getStorageContext
 import com.stevesoltys.seedvault.permitDiskReads
@@ -131,4 +132,17 @@ class StoragePluginManager(
         return storage.isUnavailableUsb(systemContext)
     }
 
+    /**
+     * Retrieves the amount of free space in bytes, or null if unknown.
+     */
+    @WorkerThread
+    suspend fun getFreeSpace(): Long? {
+        return try {
+            appPlugin.getFreeSpace()
+        } catch (e: Exception) {
+            Log.e("StoragePluginManager", "Error getting free space: ", e)
+            null
+        }
+    }
+
 }
diff --git a/app/src/main/java/com/stevesoltys/seedvault/worker/AppBackupWorker.kt b/app/src/main/java/com/stevesoltys/seedvault/worker/AppBackupWorker.kt
index 64a1cbed..e47e7e84 100644
--- a/app/src/main/java/com/stevesoltys/seedvault/worker/AppBackupWorker.kt
+++ b/app/src/main/java/com/stevesoltys/seedvault/worker/AppBackupWorker.kt
@@ -22,6 +22,7 @@ import androidx.work.OutOfQuotaPolicy.RUN_AS_NON_EXPEDITED_WORK_REQUEST
 import androidx.work.PeriodicWorkRequestBuilder
 import androidx.work.WorkManager
 import androidx.work.WorkerParameters
+import com.stevesoltys.seedvault.plugins.StoragePluginManager
 import com.stevesoltys.seedvault.settings.SettingsManager
 import com.stevesoltys.seedvault.ui.notification.BackupNotificationManager
 import com.stevesoltys.seedvault.ui.notification.NOTIFICATION_ID_OBSERVER
@@ -38,6 +39,7 @@ class AppBackupWorker(
         private val TAG = AppBackupWorker::class.simpleName
         internal const val UNIQUE_WORK_NAME = "com.stevesoltys.seedvault.APP_BACKUP"
         private const val TAG_RESCHEDULE = "com.stevesoltys.seedvault.TAG_RESCHEDULE"
+        private const val MIN_FREE_SPACE = 1024 * 1024 * 500 // 500 MB
 
         /**
          * (Re-)schedules the [AppBackupWorker].
@@ -99,6 +101,7 @@ class AppBackupWorker(
     private val backupRequester: BackupRequester by inject()
     private val settingsManager: SettingsManager by inject()
     private val apkBackupManager: ApkBackupManager by inject()
+    private val storagePluginManager: StoragePluginManager by inject()
     private val nm: BackupNotificationManager by inject()
 
     override suspend fun doWork(): Result {
@@ -108,6 +111,11 @@ class AppBackupWorker(
         } catch (e: Exception) {
             Log.e(TAG, "Error while running setForeground: ", e)
         }
+        val freeSpace = storagePluginManager.getFreeSpace()
+        if (freeSpace != null && freeSpace < MIN_FREE_SPACE) {
+            nm.onInsufficientSpaceError()
+            return Result.failure()
+        }
         return try {
             if (isStopped) {
                 Result.retry()