Lost Android Keystore? Here’s How to Recover & Continue Publishing Your App

Understanding the Problem

When you publish an Android app to the Play Store, it must be signed with a keystore file. This file contains your private key, and without it, you cannot generate valid APK/AAB updates for your existing app.

If your keystore file is deleted or lost, you cannot recreate the exact same file — the cryptographic key is unique. However, if your app is already in the Play Store, Google provides a solution: upload key reset.

What is an Upload Key?

Google Play App Signing (enabled by default for new apps) stores your original app signing key securely on Google’s servers. You use a separate upload key to sign and upload new versions.

If you lose your upload key, Google can replace it with a new one without affecting the original signing key.

Step 1: Request a New Upload Key from Google

1. Go to the Google Play Console Support page
2. Fill in the form with:
   1. App package name (e.g., com.example.android)
   2. Your developer account email
3. Confirmation that you’ve lost the key
4. Google will email you instructions to generate a new upload key and share the public certificate with them.

Step 2: Generate a New Upload Key

You can create a .jks (Java Keystore) file with this command:

keytool -genkeypair -v  -storetype JKS  -keystore my-upload-key.jks  -alias upload  -keyalg RSA  -keysize 2048  -validity 10000

You’ll be prompted for:

• Keystore password
• Key password
• Organization details
• Alias (e.g., upload)

Step 3: Export the Public Certificate

Once you create the new .jks file, export its public certificate (PEM format) and send it to Google:

keytool -export -rfc  -keystore my-upload-key.jks  -alias upload  -file upload_certificate.pem

Note: The .jks file path must match where your new file is stored.

Step 4: Update build.gradle to Use New Keystore

In your app/build.gradle:

signingConfigs {
    release {
        storeFile file('my-upload-key.jks')
        storePassword localProps['MYAPP_RELEASE_STORE_PASSWORD']
        keyAlias 'upload'
        keyPassword localProps['MYAPP_RELEASE_KEY_PASSWORD']
    }
}

Make sure local.properties contains the correct values.

.keystore vs .jks — What’s the Difference?

• .keystore – Older Java keystore format (still works but less common for new projects).
• .jks – Java KeyStore format introduced in newer Java versions (recommended now).
• Functionally, they store the same thing — the main difference is the store type (JKS vs PKCS12).

Final Tips

• Always back up your keystore file in multiple secure locations.
• Store passwords in a password manager — losing them is just as bad as losing the file.
• If Google issues a new upload key, old builds signed with the old key will still work.

In Short: If you lose your Android keystore file but your app is already on the Play Store, you can’t recover the exact file — but you can request a new upload key from Google, create a new .jks file, and keep publishing updates without starting over.