Xiaomi
Delete Face Data auf Xiaomi
Xiaomi phones running MIUI can store two separate facial profiles for Face unlock. This is meant to cover situations like wearing glasses sometimes or looking noticeably different at certain times of day.
Problems start when one of these profiles becomes outdated, for example after a major appearance change, and the system keeps comparing your face against the wrong data. Face unlock then either fails repeatedly or unlocks inconsistently. Deleting the stale profile clears that reference so you can register a current one without interference from the old data.
Where to delete face data
Open Tap on Settings ➔ Tap on Passwords & security ➔ Tap on Face unlock. Confirm your identity with Enter the current Pattern,PINor Password. Inside the Face unlock menu, Choose the Face data you want removed, then Tap on Delete face data and confirm with Tap on OK.
Once removed, that slot is free and you can set up a new facial profile from the same menu. This does not affect your PIN, pattern, or password, and any second stored face profile stays untouched.
If Face unlock still misbehaves after deleting and re-registering, check the camera lens for smudges or a case that partially covers it, since that is a common separate cause of recognition failures.