MuntashirAkon/AppManager · error · BackupException

Could not get external data backup.

Error message

Could not get external data backup.

What it means

backupData() also collects the external data archive from the EXTERNAL_FILES subdirectory when the destination flags request external data backup. If that file cannot be found, the FileNotFoundException is wrapped into this BackupException: external-data backup was requested but the corresponding zip is absent from the external-files folder.

Solutions

1. Place the external data zip inside the backup's external-files subdirectory (EXTERNAL_FILES) with the correct name.
2. Re-create the OAndBackup backup with external data included before converting.
3. If no external data exists, disable the external-data flag on the destination metadata so the lookup is skipped.
4. Verify the external-files directory name matches EXTERNAL_FILES exactly and the zip name/crypto transform matches mSourceCryptoMode.

Example fix

// before: backup/external_files/ missing entirely while external data flag is set
// after:
//   backup/external_files/com.example.app.zip
// or unset the external-data flag:
// metadataV2.flags.removeFlag(BackupFlags.BACKUP_EXT_DATA);

String extZip = CryptoUtils.getAppropriateFilename(packageName + ".zip", sourceCryptoMode);
if (destFlags.backupExternalData()) {
    if (!backupLocation.hasFile(EXTERNAL_FILES)
            || !backupLocation.findFile(EXTERNAL_FILES).hasFile(extZip)) {
        throw new IllegalStateException("External data zip missing: " + EXTERNAL_FILES + "/" + extZip);
    }
}

try {
    converter.convert(...);
} catch (BackupException e) {
    if (e.getMessage().contains("external data backup")) {
        Log.e(TAG, "external_files/<pkg>.zip not found; adjust flags or restore file", e.getCause());
    }
}

When it happens

Trigger: backupData() executes mBackupLocation.findFile(EXTERNAL_FILES).findFile(CryptoUtils.getAppropriateFilename(mPackageName + ".zip", mSourceCryptoMode)) and throws FileNotFoundException at OABConverter.java:312, with mDestMetadata.info.flags.backupExternalData() true.

Common situations: Source backup never included external data (app had none or OAndBackup backed up internal only); the external_files directory is missing or named differently; zip deleted during cleanup; crypto-mode mismatch producing a wrong expected filename.

Understand the failure class

Background: "File not found" and ENOENT errors: why libraries can't find a file that should exist — this error's family across 50 libraries.

Related errors

• Could not get backup files.
• Could not get base.apk file.
• Could not get data file
• Could not get data files
• Could not get internal data backup.

AI-assisted analysis of MuntashirAkon/AppManager@0152f468fc (2026-09-12). Data as JSON: /api/errors/a720432573fb0470. Report an issue: GitHub.

Appendix: source

Thrown at app/src/main/java/io/github/muntashirakon/AppManager/backup/convert/OABConverter.java:312

        }
    }

    private void backupData() throws BackupException {
        List<Path> dataFiles = new ArrayList<>(2);
        if (mDestMetadata.info.flags.backupInternalData()) {
            try {
                dataFiles.add(mBackupLocation.findFile(CryptoUtils.getAppropriateFilename(mPackageName + ".zip",
                        mSourceCryptoMode)));
            } catch (FileNotFoundException e) {
                throw new BackupException("Could not get internal data backup.", e);
            }
        }
        if (mDestMetadata.info.flags.backupExternalData()) {
            try {
                dataFiles.add(mBackupLocation.findFile(EXTERNAL_FILES).findFile(CryptoUtils.getAppropriateFilename(
                        mPackageName + ".zip", mSourceCryptoMode)));
            } catch (FileNotFoundException e) {
                throw new BackupException("Could not get external data backup.", e);
            }
        }
        String tarType = mDestMetadata.info.tarType;
        int i = 0;
        Path[] files;
        for (Path dataFile : dataFiles) {
            files = new Path[]{dataFile};
            // Decrypt APK file if needed
            try {
                files = ConvertUtils.decryptSourceFiles(files, mSourceCrypto, mSourceCryptoMode, mBackupItem);
            } catch (IOException e) {
                throw new BackupException("Failed to decrypt " + Arrays.toString(files), e);
            }
            // baseApkFiles should be a singleton array
            if (files.length != 1) {
                throw new BackupException("Incorrect number of APK files: " + files.length);
            }
            String dataBackupFilePrefix = BackupUtils.getDataFilePrefix(i++, getExt(tarType));

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