Face ID works through normal protectors. If it stopped after fitting one, check for a dark printed border or a bubble over the sensors at the top, and clean the top edge. Then take the protector off and try Face ID bare: if it still fails, the protector isn't the problem.
Work through these in order
- Clean the top edge of the protector. Face ID's projector and camera need a clear view, and a greasy thumbprint across the top can slow recognition.
- Look for a bubble or speck directly over the sensors, next to the Dynamic Island or notch. Lift that corner with tape, clean, and lower it again.
- Check for a dark border. Some cheap glass has a black or tinted printed edge that reaches the sensor area. If yours covers any part of the top centre, replace it with clear-edged glass.
- Test without the protector. If Face ID still fails with bare glass, restart the phone, then try Settings → Face ID & Passcode → Set Up an Alternative Appearance, or reset Face ID.
- Still failing bare? That points to a hardware fault, not your protector. Contact Apple Support.
The proximity sensor: screen not turning off on calls
The same area houses the proximity sensor that switches the screen off when the phone is at your ear. Dark printed borders cause this far more often than they affect Face ID, and it can lead to cheek-taps muting calls. It's fixed the same way: clean or replace the glass.
Privacy glass and Face ID
Privacy filters block light at an angle. Face ID looks straight out from the phone, so privacy glass doesn't block it. If recognition is slower with privacy glass, it's usually because the extra layer shows smudges more. Clean it.
Choosing glass that avoids the problem
Buy clear-edged glass from a known brand, for your exact model, with a tray so it sits centred over the sensors. If you liked the look of a black border, "case-friendly" glass from mainstream brands keeps any tint away from the sensor area.
Questions people ask
Can a screen protector stop Face ID working?
A normal one can't. A bubble, dust or a dark printed border over the sensor area can, and all are fixable.
Does privacy glass affect Face ID?
No. Face ID looks straight out, and privacy filters only block angled views.