Why does my metamask mobile app biometric lock stop working after an OS update?

28 October 2026

When you update your phone’s operating system - whether iOS or Android - the MetaMask mobile app may lose its ability to unlock using your fingerprint or face scan. This is a known, non-critical issue. The fix is usually simple: re-enable the biometric lock within MetaMask’s settings, or, if that fails, reinstall the app. The problem is not a security breach, nor does it affect your funds. It is a side effect of how OS updates handle app permissions and secure storage.

What Causes the Biometric Lock to Stop Working

MetaMask uses your device’s built-in biometric authentication (Face ID, Touch ID, or Android fingerprint) as a convenience lock. When you enable it, MetaMask stores a reference to your biometric data in a secure area of the phone’s operating system, called the Keychain on iOS or the Trusted Execution Environment on Android.

An OS update can invalidate or reset these stored references. Common triggers include:

• iOS major version updates (e.g., iOS 17 to iOS 18) often change how Face ID or Touch ID handles app data.
• Android security patches can reset app permissions or clear cached biometric tokens.
• A device restart after an update may temporarily disable biometric authentication for all apps.
• If you previously deleted and re-added your fingerprints or Face ID during the update process, the old reference MetaMask stored becomes stale.

The result: MetaMask still shows “Biometric lock enabled” in its settings, but when you try to unlock, it either fails silently, shows an error, or asks for your password instead.

How to Fix It: Step by Step

Try these solutions in order. You will not lose your wallet or your funds at any step - your seed phrase and private keys remain in the app’s encrypted storage.

1. Re-enable Biometric Lock in MetaMask Settings

This is the most common fix. The OS update may have simply “forgotten” the permission, and toggling it off and on restores the link.

1. Open the MetaMask mobile app.
2. Enter your wallet password (the one you set when creating or importing the wallet). You cannot use biometrics to do this step if the lock is already broken.
3. Tap the hamburger menu (three lines) in the top-left corner.
4. Go to Settings → Security & Privacy.
5. Find App Unlock with Face ID (iOS) or Unlock with Fingerprint (Android).
6. Toggle the switch off, then on again.
7. Your phone will prompt you to authenticate with your biometric method. Do so.
8. Lock the app by switching away and back, or by force-closing it and reopening. The biometric prompt should now work.

If the toggle is grayed out or does not respond, move to the next step.

2. check your device’s biometric settings

Sometimes the phone itself disables biometrics for all apps after an update.

• On iOS: Go to Settings → Face ID & Passcode (or Touch ID & Passcode). Make sure Face ID is enabled for MetaMask in the list under “USE FACE ID FOR OTHER APPS.” If MetaMask is not listed, the OS update may have removed it. You cannot add it manually here - proceed to step 3.
• On Android: Go to Settings → Security → Fingerprint (or Biometrics). Ensure your fingerprints are still registered. Then check Settings → Apps → MetaMask → Permissions. Confirm that “Use fingerprint” or “Biometric” is allowed.

3. Reinstall the MetaMask App

If toggling the setting fails and your device’s biometrics work for other apps, a clean reinstall usually resets the broken lock.

Important: Before you delete the app, ensure you have your seed phrase backed up. If you do not have it, do not proceed. You will lose access to your wallet if you delete the app without the seed phrase.

1. Write down or securely store your 12-word seed phrase (MetaMask’s recovery phrase). Do not take a screenshot or store it in a cloud service.
2. Delete the MetaMask app from your phone.
3. Restart your phone (this clears temporary OS cache that may still hold stale biometric references).
4. Reinstall MetaMask from the official app store (Apple App Store or Google Play Store - double-check the developer is “MetaMask”).
5. Open the app and choose Import Wallet (not “Create a new wallet”).
6. Enter your seed phrase exactly as given, word by word.
7. Set a new password.
8. Go to Settings → Security & Privacy and enable the biometric lock again.

This works because the reinstall creates a fresh biometric token that the updated OS recognizes.

4. Use Your Password as a Temporary Workaround

If none of the above works, you are not stuck. You can still open MetaMask by typing your wallet password every time. The biometric lock is a convenience feature, not a security requirement. Your funds remain accessible. You can wait for a future MetaMask update (or another OS update) to resolve the compatibility issue.

When to contact support

You should only need support if:

• You cannot remember your wallet password and the biometric lock is broken. In that case, you must use your seed phrase to recover the wallet on another device or in the browser extension.
• The app crashes immediately after the OS update and you cannot open it at all. This is rare but can happen. Reinstall as described in step 3.

Preventing This in the Future

No method prevents this entirely, but you can reduce the chance:

• Before a major OS update, temporarily disable the biometric lock in MetaMask settings. After the update, re-enable it.
• Keep the MetaMask app updated to the latest version. Developers often release patches for OS compatibility issues within a few weeks of a new OS release.

The biometric lock stopping after an OS update is an inconvenience, not a problem with your wallet or your funds. The fix is straightforward and takes only a few minutes.

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