MuntashirAkon/AppManager · error · BackupException

Could not create staging files

Error message

Could not create staging files

What it means

RestoreOp.restoreApkFiles creates placeholder APK/split-APK files in a package staging directory before decrypting and extracting the backup's tar archives. This error means creating one of those staging files (via createNewFile on packageStagingDirectory) threw an IOException. AppManager wraps it in a BackupException to abort the restore of the APK payload.

Source

Thrown at app/src/main/java/io/github/muntashirakon/AppManager/backup/RestoreOp.java:349

            }
        } catch (IOException e) {
            throw new BackupException("Could not create package staging directory", e);
        }
        synchronized (sLock) {
            // Setup apk files, including split apk
            final int splitCount = mBackupMetadata.splitConfigs.length;
            String[] allApkNames = new String[splitCount + 1];
            Path[] allApks = new Path[splitCount + 1];
            try {
                Path baseApk = packageStagingDirectory.createNewFile(mBackupMetadata.apkName, null);
                allApks[0] = baseApk;
                allApkNames[0] = mBackupMetadata.apkName;
                for (int i = 1; i < allApkNames.length; ++i) {
                    allApkNames[i] = mBackupMetadata.splitConfigs[i - 1];
                    allApks[i] = packageStagingDirectory.createNewFile(allApkNames[i], null);
                }
            } catch (IOException e) {
                throw new BackupException("Could not create staging files", e);
            }
            // Decrypt sources
            try {
                backupSourceFiles = mBackupItem.decrypt(backupSourceFiles);
            } catch (IOException e) {
                throw new BackupException("Failed to decrypt " + Arrays.toString(backupSourceFiles), e);
            }
            // Extract apk files to the package staging directory
            try {
                TarUtils.extract(mBackupInfo.tarType, backupSourceFiles, packageStagingDirectory, allApkNames, null, null);
            } catch (Throwable th) {
                throw new BackupException("Failed to extract the apk file(s).", th);
            }
            // A normal update will do it now
            InstallerOptions options = InstallerOptions.getDefault();
            options.setInstallerName(mBackupMetadata.installer);
            options.setUserId(mUserId);
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {

View on GitHub (pinned to 0152f468fc)

Solutions

1. Free up storage space on the device/partition holding the staging directory.
2. Verify the package staging directory exists and is writable before the loop (recreate it if deleted).
3. Check that backup metadata apkName/splitConfigs are non-empty and contain no path separators.
4. Re-create the backup if its metadata is corrupted; retry the restore with proper root privileges.

Example fix

// before
allApks[i] = packageStagingDirectory.createNewFile(allApkNames[i], null);
// after
if (!packageStagingDirectory.exists()) throw new BackupException("Staging dir missing");
Path staged = packageStagingDirectory.createNewFile(allApkNames[i], null);
if (staged == null) throw new BackupException("Could not create staging file: " + allApkNames[i]);
allApks[i] = staged;

if (!packageStagingDirectory.exists()) throw new IOException("Staging dir missing");
if (packageStagingDirectory.getFreeSpace() < requiredBytes) throw new IOException("Insufficient space");

boolean isWritableDir(Path d) { return d != null && d.isDirectory() && d.canWrite(); }

try { apk = staging.createNewFile(name, null); if (apk == null) throw new IOException("createNewFile returned null for " + name); } catch (IOException e) { throw new BackupException("Could not create staging files", e); }

When it happens

Trigger: packageStagingDirectory.createNewFile() fails for apkName or any of splitConfigs: staging dir missing/deleted, no write permission, storage full, or the encrypted backup file name list references an unwritable location.

Common situations: Device storage full; staging dir removed between cleanup and creation; root/privilege loss so the staging path is read-only; corrupted metadata causing invalid file names (e.g. empty or path-containing split config names).

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

• Couldn't find any writable Obb dir
• Could not delete the selected backups
• Could not create package staging directory
• Failed to decrypt ${Arrays.toString(backupSourceFiles)}
• Failed to extract the apk file(s).

AI-assisted analysis of MuntashirAkon/AppManager@0152f468fc (2026-09-12). Data as JSON: /api/errors/cfb27943f06eeeda. Report an issue: GitHub.