MuntashirAkon/AppManager · error · BackupException

Failed to backup ADB data.

Error message

Failed to backup ADB data.

What it means

backupAdb() performs an adb-style backup via BackupCompat.adbBackup and wraps any failure in this BackupException. It means the ADB-based backup stream could not be produced or written to the .ab file. The underlying Throwable is attached as cause.

Solutions

1. Check the chained cause for adbBackup failure details
2. Verify the target app allows backup (android:allowBackup) and is not blocked by device policy
3. Fall back to root-based data backup instead of ADB backup when available
4. On Android 12+ consider that adb backup is deprecated and may fail for many apps

Example fix

// before
Path[] files = backupAdb(index); // throws "Failed to backup ADB data."
// after
try {
    Path[] files = backupAdb(index);
} catch (BackupException e) {
    if (!mBackupFlags.isAdBackup()) throw e; // ADB was optional
    // surface cause to user or retry with root method
}

ApplicationInfo info = pm.getApplicationInfo(pkg, 0);
boolean adbAllowed = (info.flags & ApplicationInfo.FLAG_ALLOW_BACKUP) != 0;
if (mBackupFlags.isAdBackup() && !adbAllowed) throw new IllegalStateException("App disallows ADB backup");

try {
    Path[] files = backupAdb(index);
} catch (BackupException e) {
    Log.e(TAG, "adb backup failed", e.getCause());
    if (!flagsBackupCacheOnly) rethrow;
}

When it happens

Trigger: BackupCompat.adbBackup(...) throws (backup agent unavailable, device refuses ADB backup, fd/IO errors) or writing the resulting abFile fails inside backupAdb().

Common situations: Target app sets allowBackup=false; Android 12+ deprecating adb backup; device policy blocking backup; user not confirming backup on device.

Understand the failure class

Background: "API request failed": what wrapped HTTP errors from external APIs mean and how to find the real cause — this error's family across 29 libraries.

Related errors

• ADB restore is requested but there are no .ab files.
• Failed to restore ADB data
• ADB command did not produce
• ADB daemon not running.
• An uninstallation was necessary but couldn't perform it.

AI-assisted analysis of MuntashirAkon/AppManager@0152f468fc (2026-09-12). Data as JSON: /api/errors/03b9d07fb1c8f5ae. Report an issue: GitHub.

Appendix: source

Thrown at app/src/main/java/io/github/muntashirakon/AppManager/backup/BackupOp.java:391

        } catch (Throwable th) {
            throw new BackupException("Failed to backup data directory at " + dir, th);
        }
    }

    @NonNull
    private Path[] backupAdb(int index) throws BackupException {
        try {
            String filePrefix = BackupUtils.getDataFilePrefix(index, ".ab");
            Path abFile = mBackupItem.getUnencryptedBackupPath().createNewFile(filePrefix, null);
            try (OutputStream os = abFile.openOutputStream()) {
                ParcelFileDescriptor fd = ParcelFileDescriptorUtil.pipeTo(os);
                BackupCompat.adbBackup(mUserId, fd, false, false, false,
                        false, false, false, false, true,
                        new String[]{mPackageName});
            }
            return new Path[]{abFile};
        } catch (Throwable th) {
            throw new BackupException("Failed to backup ADB data.", th);
        }
    }

    private void backupKeyStore() throws BackupException {  // Called only when the app has an keystore item
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {
            // keystore v2 is not supported.
            Log.w(TAG, "Ignoring KeyStore backups for %s", mPackageName);
            return;
        }
        Path keyStorePath = KeyStoreUtils.getKeyStorePath(mUserId);
        try {
            Path masterKeyFile = KeyStoreUtils.getMasterKey(mUserId);
            // Master key exists, so take its checksum to verify it during the restore
            mChecksum.add(MASTER_KEY, DigestUtils.getHexDigest(mMetadata.info.checksumAlgo,
                    masterKeyFile.getContentAsString().getBytes()));
        } catch (FileNotFoundException ignore) {
        }
        // Store the KeyStore files

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