MuntashirAkon/AppManager · error · BackupException

Could not backup KeyStore item.

Error message

Could not backup KeyStore item.

What it means

After caching keystore files, backupKeyStore() creates a tar archive of them via TarUtils.create into the backup path. Any Throwable from archive creation is wrapped as this BackupException with the cause preserved.

Source

Thrown at app/src/main/java/io/github/muntashirakon/AppManager/backup/BackupOp.java:434

                        String.valueOf(KEYSTORE_PLACEHOLDER));
                IoUtils.copy(keyStorePath.findFile(keyStoreFileName), cachePath.findOrCreateFile(newFileName, null));
                cachedKeyStoreFileNames.add(newFileName);
                keyStoreFilters.add(Pattern.quote(newFileName));
            } catch (Throwable e) {
                throw new BackupException("Could not cache " + keyStoreFileName, e);
            }
        }
        if (cachedKeyStoreFileNames.isEmpty()) {
            throw new BackupException("There were some KeyStore items but they couldn't be cached before taking a backup.");
        }
        String keyStorePrefix = KEYSTORE_PREFIX + getExt(mMetadata.info.tarType);
        Path[] backedUpKeyStoreFiles;
        try {
            backedUpKeyStoreFiles = TarUtils.create(mMetadata.info.tarType, cachePath, mBackupItem.getUnencryptedBackupPath(), keyStorePrefix,
                            keyStoreFilters.toArray(new String[0]), null, null, false)
                    .toArray(new Path[0]);
        } catch (Throwable th) {
            throw new BackupException("Could not backup KeyStore item.", th);
        }
        // Remove cache
        for (String name : cachedKeyStoreFileNames) {
            try {
                cachePath.findFile(name).delete();
            } catch (FileNotFoundException ignore) {
            }
        }
        try {
            backedUpKeyStoreFiles = mBackupItem.encrypt(backedUpKeyStoreFiles);
        } catch (IOException e) {
            throw new BackupException("Failed to encrypt " + Arrays.toString(backedUpKeyStoreFiles), e);
        }
        for (Path file : backedUpKeyStoreFiles) {
            mChecksum.add(file.getName(), DigestUtils.getHexDigest(mMetadata.info.checksumAlgo, file));
        }
    }

View on GitHub (pinned to 0152f468fc)

Solutions

1. Check chained cause for the tar/I/O failure
2. Confirm cache files still exist right before TarUtils.create
3. Verify mMetadata.info.tarType is a supported TAR_TYPES value
4. Check free space and write permission on the backup directory

Example fix

// before
backedUpKeyStoreFiles = TarUtils.create(...).toArray(new Path[0]);
// after
try {
    backedUpKeyStoreFiles = TarUtils.create(...).toArray(new Path[0]);
} catch (Throwable th) {
    throw new BackupException("Could not backup KeyStore item.", th);
} // caller: retry once after re-caching keystore files

if (!Arrays.stream(TarUtils.TAR_TYPES).anyMatch(t -> t.equals(mMetadata.info.tarType)))
    throw new IllegalArgumentException("bad tarType");
if (cachePath.findFile(firstCached) == null) throw new IllegalStateException("cache files vanished");

try {
    backedUpKeyStoreFiles = TarUtils.create(...).toArray(new Path[0]);
} catch (Throwable th) {
    Log.e(TAG, "keystore tar failed", th);
    throw new BackupException("Could not backup KeyStore item.", th);
}

When it happens

Trigger: TarUtils.create(tarType, cachePath, backupPath, keyStorePrefix, filters, ...) throws — I/O error writing the tar, invalid tarType, or cache files vanished between caching and archiving.

Common situations: Cache files deleted prematurely; storage full on backup destination; unsupported tarType in metadata; encrypted-target directory not writable.

Understand the failure class

Background: "failed to write file", "Could not save figure", "Error saving remote file" — file write failed: causes and fixes across languages and libraries — this error's family across 38 libraries.

Related errors

• Failed to backup data directory at
• Could not cache
• Backup failed for
• APK files backup is requested but no APK files have been bac
• Backup failed for

AI-assisted analysis of MuntashirAkon/AppManager@0152f468fc (2026-09-12). Data as JSON: /api/errors/dcef6c5269e49985. Report an issue: GitHub.