An Android app that resets suddenly and wipes all your data usually points to an android sqlite database corrupted error. Apps store data in SQLite through SQLiteOpenHelper or the Room library. Android's DefaultDatabaseErrorHandler responds to corruption by deleting the database file. The app starts empty. Here is why that happens and how to recover the data.

How SQLite Corruption Happens on Android

SQLite corruption occurs when an app crashes mid-write, when the device runs out of storage, or when the file system fails. Android throws an android.database.sqlite.SQLiteDatabaseCorruptException at that moment. Without a custom handler, the database gets deleted and the app starts fresh. No warning. No prompt.

Why the Default Handler Deletes Your Data

Android's DefaultDatabaseErrorHandler stops apps from crashing repeatedly by deleting the corrupt database file. After a crash, the app appears to have reset. User progress, settings, and stored data vanish. This is the mechanism behind an android app data reset after crash.

The deletion is silent. The app creates a new empty database on the next launch. The original data might still be recoverable if a copy was made before deletion. Make that copy. That is the single step that changes the outcome.

Where App Databases Are Stored

Accessing the Private Data Directory

App databases live in the private data directory at /data/data/<package>/databases/. Normal users cannot browse this location through a standard file manager on an unmodified phone. The directory is sandboxed per app.

To reach it, use a rooted device or a backup tool that reads internal storage. Extract the database file from a backup, or run a recovery tool against the raw file system.

What Developers Can Do Differently

Developers can copy the database to an external location programmatically before corruption strikes. Do this early. A copy made after the fact is too late.

How Developers Can Prevent Silent Data Loss

Pass a custom DatabaseErrorHandler to change the default behaviour. Keep a copy for recovery. Here is the approach:

  1. Create a custom class that implements DatabaseErrorHandler.
  2. In the onCorruption method, copy the database file and its -wal file to a backup directory before the default handler deletes them.
  3. Pass an instance of your custom handler to SQLiteOpenHelper or Room when opening the database.

If you use Room, set a custom callback during database creation. Room uses WAL journal mode by default on devices that support it, so a -wal file sits alongside the main database. Include that -wal file in your copy, or checkpoint the database first. Without it, the copy may be incomplete.

Recovering a Corrupted Database After Deletion

If the database was already deleted by the default handler, recovery depends on whether you have a backup. No backup means the file is gone from the app's private directory. A prior copy, or a system backup, gives you a path forward.

Checkpointing Before Copying

Before copying a database from a running app, checkpoint it. Execute PRAGMA wal_checkpoint; in SQLite to merge the -wal file. Then copy only the main database file.

Using a Recovery Service

Upload a copy of the database file to sqlite.repair. The service handles many common corruption patterns. It is free and adds no watermark to the output.

What Power Users Can Do to Safeguard Data

Protect your app data before a recover android app database emergency hits. Take these steps:

  • Enable app backups through Android's built-in backup or a third-party tool.
  • If you have root access, copy the contents of /data/data/<package>/databases/ to external storage on a schedule.
  • Let apps finish their transactions. Do not force-close an app that is writing data.

These measures cut the chance of encountering a corrupt database. They also give you a fallback when corruption does occur.

Summary of Key Takeaways

An Android app that loses its data after a crash points to the DefaultDatabaseErrorHandler deleting a corrupt SQLite database. Override this behaviour with a custom handler that backs up the file first. Power users with root access can copy databases manually from the app's private directory. In every case, include the -wal file when copying. A checkpointed copy is a complete copy. If you already hold a copy of the corrupted database, upload it to sqlite.repair for recovery.