The Galaxy Z Flip5 has its fingerprint reader built into the side power key, not under the screen, and it also offers face recognition on both the inner and the cover screens, and the fold itself affects how unlocking behaves. The side reader is a capacitive sensor that reads a finger resting on the key, so a thumb that taps instead of resting will not register, and a damp or dirty finger fails.
The checks in more detail
Open Settings, Security and privacy, Biometrics, Fingerprints and re-register the finger by resting it on the key and lifting between prompts. Register the same finger two or three times and add a second. Clean the key with a dry cloth. A case with a cut-out that presses on the key or a thick protective film can interfere. The fold matters for face recognition. The phone can unlock with its face recognition on the inner screen when open and, depending on the setting, with the cover screen, and the front camera needs to see you.
Make sure the lens on the cover and the inner camera is clean, register your face in good light and add an alternative look if you wear glasses. Check that the setting that lets the phone unlock when the cover screen shows a widget is not confusing you. Remember that face recognition is less secure than a fingerprint and some apps ask for a fingerprint or PIN anyway. After a restart, an update or too many failed attempts the phone asks for the PIN, which is normal.
If the reader responds slowly, update the software and restart. A fault that began after a fall may point to the key's flex cable or the frame, and Samsung's service can test it. Do not press hard on the inner screen or peel its film while you work on the phone. If the reader does not respond at all, run the diagnostics in Samsung Members and contact Samsung with the serial number. Keep the PIN safe, since it is always the fallback, and set a screen lock that you will remember.
Differential
Likely causes of “Samsung Galaxy Z Flip5 biometric unlock is not working”, and how to tell them apart
- 1
A finger that taps instead of rests
What separates it The side key does not read
How to confirm Rest the finger on the key and register again
- 2
A dirty key or a case that presses on it
What separates it Reads fail at random
How to confirm Clean the key and check the case
- 3
A stale registration
What separates it The phone no longer recognizes you
How to confirm Delete and register the finger twice
- 4
A dirty camera on the cover or inner screen
What separates it Face unlock fails
How to confirm Clean the lens and register in good light
- 5
A fall or flex-cable fault
What separates it Nothing registers
How to confirm Samsung service
Before you touch a setting
Record this first — changing settings destroys the evidence
- Whether the key or face fails
- Whether a case is fitted
- Whether the phone was dropped
- The software version
Try in this order
0 of 6 completedClean the key
ReversibleAnd remove the case.
Rest the finger on the key
ReversibleDo not tap.
Register the finger twice
ReversibleAnd add a second.
Check the cameras
ReversibleOn both screens.
Update and restart
ReversibleThe phone.
Run diagnostics
ReversibleIn Samsung Members.
Model-specific
What is true of this model and not of its siblings
- Side key
- The reader is in the power key.
- Fold
- The folded phone has two cameras for face unlock.
- Using the cover screen
- The Flip5's cover screen can unlock the phone with the fingerprint reader in the side key while the phone is closed, which many owners prefer to opening it. Register the same finger that falls on the key when you hold the closed phone, and the other thumb for when it is open. The key's flat face is small, so rest the finger across its width.
- Hinge and heat
- A phone that has been folded in a warm pocket may have a slightly damp or warm key that reads poorly. Wipe the key and let the phone cool before you judge the sensor.
Stop boundary
When this stops being a self-service repair
- !If the key does not respond at all, contact Samsung with the serial number
- !Do not peel the inner screen's film
- !Remember the PIN
Evidence ledger
Sources behind this answer
Exact questions
Common questions
Where is the Flip5 fingerprint reader?+
In the side power key.
Does face unlock work on the cover screen?+
Depending on the setting, yes.
Why does it ask for the PIN?+
After a restart or an update it always does.
What if I dropped it?+
The key's cable may need service.
Which finger should I register?+
The one that falls on the side key when you hold the closed phone.