MuntashirAkon/AppManager · error · BackupException

Cannot convert special backup " + mPackageName

Error message

Cannot convert special backup " + mPackageName

What it means

OABConverter refuses to convert OAndBackup entries whose package name is in the SPECIAL_BACKUPS set (App Manager's own metadata/special packages). Converting them would produce invalid App Manager backups, so convert() throws BackupException up front.

Solutions

1. Skip packages in SPECIAL_BACKUPS instead of converting them
2. Filter the list of OAB backup directories before instantiating OABConverter
3. If the package is genuinely needed, create a fresh App Manager backup rather than converting

Example fix

// before
new OABConverter(userId, packageName).convert();
// after
if (!SPECIAL_BACKUPS.contains(packageName)) {
    new OABConverter(userId, packageName).convert();
}

if (SPECIAL_BACKUPS.contains(packageName)) {
    Log.i(TAG, "Skipping special backup: " + packageName);
    return;
}

try {
    converter.convert();
} catch (BackupException e) {
    if (e.getMessage() != null && e.getMessage().startsWith("Cannot convert special backup")) {
        // skip package, continue batch
    }
}

When it happens

Trigger: Calling OABConverter.convert() with mPackageName set to a package listed in SPECIAL_BACKUPS (e.g. the converter tool's own special backup entries).

Common situations: Batch-converting an entire OAndBackup directory that includes special/system entries the user never installed manually; scripting conversion over all folders without filtering.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• Android System (android) cannot be backed up.
• Could not finalise backup.
• Could not get backup files.
• Empty JSON string.
• Failed to get crypto " + mDestMetadata.info.crypto

AI-assisted analysis of MuntashirAkon/AppManager@0152f468fc (2026-09-12). Data as JSON: /api/errors/f6a544b8f92e9b66. Report an issue: GitHub.

Appendix: source

Thrown at app/src/main/java/io/github/muntashirakon/AppManager/backup/convert/OABConverter.java:109

    private String mSourceCryptoMode;
    private Crypto mSourceCrypto;
    private BackupMetadataV5 mDestMetadata;
    private BackupItems.BackupItem mBackupItem;

    /**
     * @param backupLocation E.g. {@code /sdcard/oandbackups/package.name}
     */
    public OABConverter(@NonNull Path backupLocation) {
        mBackupLocation = backupLocation;
        // Last path component is the package name
        mPackageName = backupLocation.getName();
        mUserId = UserHandleHidden.myUserId();
    }

    @Override
    public void convert() throws BackupException {
        if (SPECIAL_BACKUPS.contains(mPackageName)) {
            throw new BackupException("Cannot convert special backup " + mPackageName);
        }
        // Source metadata
        mSourceMetadata = readLogFile();
        // Simulate a backup creation
        try {
            mBackupItem = BackupItems.createBackupItemGracefully(mUserId, "OAndBackup", mPackageName);
        } catch (IOException e) {
            throw new BackupException("Could not get backup files.", e);
        }
        boolean backupSuccess = false;
        try {
            try {
                // Destination metadata
                mDestMetadata = ConvertUtils.getV5Metadata(mSourceMetadata, mBackupItem);
            } catch (CryptoException e) {
                throw new BackupException("Failed to get crypto " + mDestMetadata.info.crypto, e);
            }
            try {

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