MuntashirAkon/AppManager · error · BackupException

Could not read the prop file

Error message

Could not read the prop file

What it means

readPropFile() opens the prop file via mPropFile.openInputStream() and reads its properties; any IOException during reading or parsing is rethrown as BackupException("Could not read the prop file", e). It signals the backup's metadata file is unreadable, so conversion cannot discover app name, version, flags, or codec.

Source

Thrown at app/src/main/java/io/github/muntashirakon/AppManager/backup/convert/TBConverter.java:425

            }
            try {
                mFilesToBeDeleted.add(getApkFile(metadataV2.apkName, metadataV2.tarType));
                // No error = APK file exists
                metadataV2.flags.addFlag(BackupFlags.BACKUP_APK_FILES);
            } catch (FileNotFoundException ignore) {
            }
            metadataV2.dataDirs = ConvertUtils.getDataDirs(mPackageName, mUserId, metadataV2.flags
                    .backupInternalData(), metadataV2.flags.backupExternalData(), false);
            metadataV2.keyStore = false;
            metadataV2.installer = Prefs.Installer.getInstallerPackageName();
            String base64Icon = prop.getProperty("app_gui_icon");
            if (base64Icon != null) {
                byte[] decodedBytes = Base64.decode(base64Icon, 0);
                mIcon = BitmapFactory.decodeByteArray(decodedBytes, 0, decodedBytes.length);
            }
            return metadataV2;
        } catch (IOException e) {
            throw new BackupException("Could not read the prop file", e);
        }
    }

    @NonNull
    private Path getDataFile(String filePrefix, @TarUtils.TarType String tarType) throws FileNotFoundException {
        String filename = filePrefix + ".tar";
        if (TAR_BZIP2.equals(tarType)) filename += ".bz2";
        else if (TAR_ZSTD.equals(tarType)) filename += ".zst";
        else filename += ".gz";
        return mBackupLocation.findFile(filename);
    }

    @NonNull
    private Path getApkFile(String apkName, @TarUtils.TarType String tarType) throws FileNotFoundException {
        if (TAR_BZIP2.equals(tarType)) apkName += ".bz2";
        else if (TAR_ZSTD.equals(tarType)) apkName += ".zst";
        else apkName += ".gz";
        return mBackupLocation.findFile(apkName);

View on GitHub (pinned to 0152f468fc)

Solutions

1. Confirm the .prop file exists next to the tar data file and the path passed to TBConverter points to it.
2. Check file permissions and storage state (mounted, readable) for the backup directory.
3. Re-copy the backup set completely (prop + tar + icons) from the source device.
4. Inspect e.getCause() to distinguish missing-file from mid-read I/O errors.

Example fix

// before
converter.convert(new File("/backup/app"));
// after
File prop = new File("/backup/app", "app.prop");
if (!prop.canRead()) {
    throw new IllegalStateException("Prop file missing/unreadable: " + prop);
}
converter.convert(new File("/backup/app"));

File prop = new File(backupDir, backupDir.getName() + ".prop");
if (!prop.isFile() || !prop.canRead())
    throw new IllegalStateException("Prop file missing or unreadable: " + prop);

try {
    converter.convert(backupDir);
} catch (BackupException e) {
    if (e.getMessage() != null && e.getMessage().contains("Could not read the prop file")) {
        Log.e(TAG, "Unreadable prop", e.getCause()); // check permissions/media state
    } else throw e;
}

When it happens

Trigger: Calling convert() on a backup where the .prop file cannot be opened or read: missing file, permission denied, I/O error on the storage device, or a stream failure mid-read (e.g. after icon Base64 decoding).

Common situations: Pointing the converter at a directory without its prop file; SD card unmounted or corrupted; files copied over MTP losing metadata; restrictive file permissions after restore from another device.

Understand the failure class

Background: "failed to read file", EACCES, ENOENT and "could not read <path>" errors: when a program can't read a file from disk — this error's family across 49 libraries.

Related errors

• Unsupported compression type: ${compressionType}
• Couldn't delete old file <inputFile>
• Could not delete <mBackupPath>
• Could not move <mTempBackupPath> to <mBackupPath>
• Android System (android) cannot be backed up.

AI-assisted analysis of MuntashirAkon/AppManager@0152f468fc (2026-09-12). Data as JSON: /api/errors/27507097521cddd3. Report an issue: GitHub.