diff --git a/mobile/src/main/java/de/tstratmann/gpstracker/ActivitiesActivity.kt b/mobile/src/main/java/de/tstratmann/gpstracker/ActivitiesActivity.kt
index 0c14fea..67b7639 100644
--- a/mobile/src/main/java/de/tstratmann/gpstracker/ActivitiesActivity.kt
+++ b/mobile/src/main/java/de/tstratmann/gpstracker/ActivitiesActivity.kt
@@ -20,6 +20,10 @@ import com.google.gson.Gson
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
+import java.io.BufferedOutputStream
+import java.util.zip.ZipEntry
+import java.util.zip.ZipInputStream
+import java.util.zip.ZipOutputStream
 
 class ActivitiesActivity : AppCompatActivity() {
 
@@ -35,14 +39,16 @@ class ActivitiesActivity : AppCompatActivity() {
         uri?.let { importGpxFile(it) }
     }
 
-    private val backupFolderLauncher = registerForActivityResult(
-        ActivityResultContracts.OpenDocumentTree()
+    // Backup: Wir erstellen eine ZIP-Datei
+    private val createBackupLauncher = registerForActivityResult(
+        ActivityResultContracts.CreateDocument("application/zip")
     ) { uri ->
         uri?.let { performDriveBackup(it) }
     }
 
-    private val restoreFolderLauncher = registerForActivityResult(
-        ActivityResultContracts.OpenDocumentTree()
+    // Restore: Wir wählen eine ZIP-Datei aus
+    private val restoreBackupLauncher = registerForActivityResult(
+        ActivityResultContracts.OpenDocument()
     ) { uri ->
         uri?.let { performDriveRestore(it) }
     }
@@ -77,11 +83,12 @@ class ActivitiesActivity : AppCompatActivity() {
     override fun onOptionsItemSelected(item: MenuItem): Boolean {
         return when (item.itemId) {
             R.id.action_drive_backup -> {
-                backupFolderLauncher.launch(googleDriveUri())
+                val date = java.text.SimpleDateFormat("yyyy-MM-dd", java.util.Locale.getDefault()).format(java.util.Date())
+                createBackupLauncher.launch("gpstracker_backup_$date.zip")
                 true
             }
             R.id.action_drive_restore -> {
-                restoreFolderLauncher.launch(googleDriveUri())
+                restoreBackupLauncher.launch(arrayOf("application/zip", "application/x-zip-compressed"))
                 true
             }
             R.id.action_import_gpx -> {
@@ -92,10 +99,7 @@ class ActivitiesActivity : AppCompatActivity() {
         }
     }
 
-    private fun googleDriveUri(): Uri =
-        Uri.parse("content://com.google.android.apps.docs.storage/")
-
-    private fun performDriveBackup(folderUri: Uri) {
+    private fun performDriveBackup(fileUri: Uri) {
         val tracks = trackStorage.getAllTracks()
         if (tracks.isEmpty()) {
             Toast.makeText(this, "Keine Tracks zum Sichern", Toast.LENGTH_SHORT).show()
@@ -104,39 +108,28 @@ class ActivitiesActivity : AppCompatActivity() {
 
         lifecycleScope.launch(Dispatchers.IO) {
             try {
-                val folder = DocumentFile.fromTreeUri(this@ActivitiesActivity, folderUri)
-                if (folder == null || !folder.canWrite()) {
-                    withContext(Dispatchers.Main) {
-                        Toast.makeText(this@ActivitiesActivity, "Ordner nicht beschreibbar", Toast.LENGTH_LONG).show()
-                    }
-                    return@launch
-                }
+                contentResolver.openOutputStream(fileUri)?.use { os ->
+                    ZipOutputStream(BufferedOutputStream(os)).use { zos ->
+                        tracks.forEach { track ->
+                            val safeName = trackStorage.sanitizeFileName(track.name)
+                            
+                            // JSON Datei in ZIP
+                            val jsonEntry = ZipEntry("$safeName.json")
+                            zos.putNextEntry(jsonEntry)
+                            zos.write(gson.toJson(track).toByteArray(Charsets.UTF_8))
+                            zos.closeEntry()
 
-                var count = 0
-                tracks.forEach { track ->
-                    val safeName = track.name.replace(Regex("[^a-zA-Z0-9._-]"), "_")
-
-                    val jsonName = "$safeName.json"
-                    folder.findFile(jsonName)?.delete()
-                    folder.createFile("application/json", jsonName)?.let { doc ->
-                        contentResolver.openOutputStream(doc.uri)?.use { os ->
-                            os.write(gson.toJson(track).toByteArray(Charsets.UTF_8))
+                            // GPX Datei in ZIP
+                            val gpxEntry = ZipEntry("$safeName.gpx")
+                            zos.putNextEntry(gpxEntry)
+                            zos.write(gpxExporter.generateGpxContent(track).toByteArray(Charsets.UTF_8))
+                            zos.closeEntry()
                         }
                     }
-
-                    val gpxName = "$safeName.gpx"
-                    folder.findFile(gpxName)?.delete()
-                    folder.createFile("application/gpx+xml", gpxName)?.let { doc ->
-                        contentResolver.openOutputStream(doc.uri)?.use { os ->
-                            os.write(gpxExporter.generateGpxContent(track).toByteArray(Charsets.UTF_8))
-                        }
-                    }
-
-                    count++
                 }
 
                 withContext(Dispatchers.Main) {
-                    Toast.makeText(this@ActivitiesActivity, "$count Track(s) gesichert (JSON + GPX)", Toast.LENGTH_LONG).show()
+                    Toast.makeText(this@ActivitiesActivity, "${tracks.size} Tracks in Backup gesichert", Toast.LENGTH_LONG).show()
                 }
             } catch (e: Exception) {
                 withContext(Dispatchers.Main) {
@@ -146,42 +139,35 @@ class ActivitiesActivity : AppCompatActivity() {
         }
     }
 
-    private fun performDriveRestore(folderUri: Uri) {
+    private fun performDriveRestore(fileUri: Uri) {
         lifecycleScope.launch(Dispatchers.IO) {
             try {
-                val folder = DocumentFile.fromTreeUri(this@ActivitiesActivity, folderUri)
-                if (folder == null) {
-                    withContext(Dispatchers.Main) {
-                        Toast.makeText(this@ActivitiesActivity, "Ordner nicht zugänglich", Toast.LENGTH_LONG).show()
-                    }
-                    return@launch
-                }
-
-                val files = folder.listFiles()
-                val jsonFiles = files.filter { it.name?.endsWith(".json") == true }
-                val gpxFiles = files.filter { it.name?.endsWith(".gpx") == true }
-                val jsonNames = jsonFiles.map { it.name!!.removeSuffix(".json") }.toSet()
-
                 var restored = 0
                 var skipped = 0
 
-                jsonFiles.forEach { file ->
-                    contentResolver.openInputStream(file.uri)?.use { inputStream ->
-                        val content = inputStream.readBytes().toString(Charsets.UTF_8)
-                        val track = runCatching { gson.fromJson(content, Track::class.java) }.getOrNull()
-                        if (track != null) {
-                            if (trackStorage.getTrack(track.name) == null) { trackStorage.saveTrack(track); restored++ } else skipped++
+                contentResolver.openInputStream(fileUri)?.use { inputStream ->
+                    ZipInputStream(inputStream).use { zis ->
+                        var entry = zis.nextEntry
+                        while (entry != null) {
+                            if (!entry.isDirectory && entry.name.endsWith(".json")) {
+                                val content = zis.readBytes().toString(Charsets.UTF_8)
+                                val track = runCatching { gson.fromJson(content, Track::class.java) }.getOrNull()
+                                
+                                if (track != null) {
+                                    if (trackStorage.getTrack(track.name) == null) {
+                                        trackStorage.saveTrack(track)
+                                        restored++
+                                    } else {
+                                        skipped++
+                                    }
+                                }
+                            }
+                            zis.closeEntry()
+                            entry = zis.nextEntry
                         }
                     }
                 }
 
-                gpxFiles.filter { it.name?.removeSuffix(".gpx") !in jsonNames }.forEach { file ->
-                    val track = gpxImporter.importFromUri(file.uri)
-                    if (track != null) {
-                        if (trackStorage.getTrack(track.name) == null) { trackStorage.saveTrack(track); restored++ } else skipped++
-                    }
-                }
-
                 withContext(Dispatchers.Main) {
                     val msg = buildString {
                         append("$restored Track(s) wiederhergestellt")
@@ -206,7 +192,6 @@ class ActivitiesActivity : AppCompatActivity() {
 
     private fun loadAndDisplayTracks() {
         val tracks = trackStorage.getAllTracks()
-
         binding.tracksContainer.removeAllViews()
 
         if (tracks.isEmpty()) {