MuntashirAkon/AppManager · error · BackupException

Failed to decrypt ${miscFile.getName()}

Error message

Failed to decrypt ${miscFile.getName()}

What it means

Thrown by loadMiscRules when decrypting the misc (permissions) file via mBackupItem.decrypt throws IOException or IndexOutOfBoundsException. It indicates the encrypted misc file could not be decrypted into a usable Path, usually because of a wrong password, missing crypto material, or an empty/absent result array.

Source

Thrown at app/src/main/java/io/github/muntashirakon/AppManager/backup/RestoreOp.java:743

            miscFile = mBackupItem.getMiscFile();
        } catch (IOException e) {
            // There are no permissions, just skip
            return;
        }
        if (!mRequestedFlags.skipSignatureCheck()) {
            String checksum = DigestUtils.getHexDigest(mBackupInfo.checksumAlgo, miscFile);
            if (!checksum.equals(mChecksum.get(miscFile.getName()))) {
                throw new BackupException("Couldn't verify misc file." +
                        "\nFile: " + miscFile +
                        "\nFound: " + checksum +
                        "\nRequired: " + mChecksum.get(miscFile.getName()));
            }
        }
        // Decrypt permission file
        try {
            miscFile = mBackupItem.decrypt(new Path[]{miscFile})[0];
        } catch (IOException | IndexOutOfBoundsException e) {
            throw new BackupException("Failed to decrypt " + miscFile.getName(), e);
        }
        try {
            rules.loadExternalEntries(miscFile);
        } catch (Throwable e) {
            throw new BackupException("Failed to load rules from misc.", e);
        }
    }

    private void restoreRules() throws BackupException {
        // Apply rules
        if (!mIsInstalled) {
            throw new BackupException("Rules restore is requested but the app isn't installed.");
        }
        Path rulesFile;
        try {
            rulesFile = mBackupItem.getRulesFile();
        } catch (IOException e) {
            if (mBackupMetadata.hasRules) {

View on GitHub (pinned to 0152f468fc)

Solutions

1. Provide the correct encryption password for the backup
2. Check the misc file exists, is non-empty, and matches its recorded size/checksum
3. Ensure the backup's crypto/key files were copied along with the misc file
4. Re-create the backup with encryption enabled and verified if the file is corrupt

Example fix

// before
miscFile = mBackupItem.decrypt(new Path[]{miscFile})[0]; // raw call, same failure
// after
Path[] decrypted = mBackupItem.decrypt(new Path[]{miscFile});
if (decrypted == null || decrypted.length == 0) {
    Log.e(TAG, "Decryption produced no output for " + miscFile.getName());
    return;
}
miscFile = decrypted[0];

if (!miscFile.exists() || miscFile.size() == 0) {
    throw new IllegalStateException("Misc file missing or empty — decryption will fail");
}

try {
    restoreOp.runRestore();
} catch (BackupException e) {
    if (e.getMessage().startsWith("Failed to decrypt")) {
        rePromptForPassword("Misc file decryption failed");
    } else throw e;
}

When it happens

Trigger: mBackupItem.decrypt(new Path[]{miscFile}) throws IOException (bad password, corrupt file, I/O failure) or IndexOutOfBoundsException (decrypt returned an empty array — no decrypted output produced).

Common situations: Wrong decryption password for an encrypted backup; the misc file was not fully copied or is zero bytes; encryption keys absent from the backup; the backup is unencrypted but the decrypt path was still invoked with no matching key.

Understand the failure class

Background: Checksum mismatch errors: "checksum verification failed", "digest mismatch", "expected vs actual checksum" — what they mean and how to fix them — this error's family across 41 libraries.

Related errors

• Failed to decrypt ${Arrays.toString(dataFiles)}
• Failed to decrypt
• Couldn't delete old file <inputFile>
• Failed to write checksums.txt
• Failed to encrypt

AI-assisted analysis of MuntashirAkon/AppManager@0152f468fc (2026-09-12). Data as JSON: /api/errors/4663c1dd037007c8. Report an issue: GitHub.