The Galaxy S26+ unlocks with an ultrasonic fingerprint sensor under the screen and with face recognition through the front camera, and a fault with either is nearly always a registration, a cover or a software matter. If the fingerprint sensor stops reading, first clean the screen and your finger, since a damp or oily finger or a smudge over the sensor makes the reading fail, although ultrasonic sensors cope with dampness better than optical ones.
The checks in more detail
Check that no screen protector is covering the sensor area, because a protector that was not made for ultrasonic sensors, or one that has an air gap, will block it; Samsung recommends protectors that are designed for the phone. Open Settings, Security and privacy, Biometrics, Fingerprints and make sure the feature is on and unlocking the phone is allowed. Registering the finger again is the usual cure. Delete the saved fingerprint and add it afresh, pressing the finger flat and covering the whole sensor, and register the same finger a second time so that the phone has two views of it. Register more than one finger as a backup.
If the phone has had a new protector fitted, add the finger again afterwards, because the sensor learns it through the protector. For face recognition, find it in the same menu and check that the camera lens is clean, and register in good light without a hat or heavy glasses; Samsung notes that face recognition is less secure than a fingerprint, so banking apps may ask for a fingerprint or a PIN anyway. The phone will always ask for the PIN after a restart or an update, after too many failed tries and every so often as a safety check, and that is not a fault.
If a fingerprint stops working after a software update, install the newest patch and restart. Apps that use biometrics may need to be told to use them again. A work profile or a device-management policy can disable biometrics, so check with the administrator. Test the sensor in the diagnostics in the Samsung Members app. If the sensor does not respond at all after these steps and a protector is not the cause, the phone may need service, and Samsung can test it with the serial number. Keep your PIN somewhere safe, since it is the key to the phone.
Differential
Likely causes of “Samsung Galaxy S26+ biometric unlock is not working”, and how to tell them apart
- 1
A protector that blocks the ultrasonic sensor
What separates it The fingerprint is not read
How to confirm Use a protector made for the phone and register again
- 2
A dirty screen or finger
What separates it Reads fail at random
How to confirm Clean both and try again
- 3
A registration that has gone stale
What separates it The phone no longer recognizes you
How to confirm Delete and register the finger twice
- 4
A restart or update
What separates it The phone asks for the PIN
How to confirm Enter the PIN once
- 5
A management policy
What separates it Biometrics are grayed out
How to confirm Check the work profile settings
Before you touch a setting
Record this first — changing settings destroys the evidence
- Whether a protector is fitted
- Whether face or fingerprint fails
- Whether it began after an update
- The software version
Try in this order
0 of 6 completedClean screen and finger
ReversibleAnd remove any protector as a test.
Delete the fingerprint
ReversibleAnd register it again.
Register a second finger
ReversibleAs a backup.
Check face recognition
ReversibleIn good light.
Update the software
ReversibleAnd restart.
Run diagnostics
ReversibleIn Samsung Members.
Model-specific
What is true of this model and not of its siblings
- Protectors
- Use one made for the phone.
- PIN
- Required after a restart.
Stop boundary
When this stops being a self-service repair
- !If the sensor does not respond after a protector check and a re-registration, contact Samsung with the serial number
- !Remember the PIN
- !Install the newest update
Evidence ledger
Sources behind this answer
Exact questions
Common questions
Why does my S26+ fingerprint fail?+
Often a protector or a stale registration.
Does the S26+ use ultrasonic or optical?+
Ultrasonic, under the screen.
Why does it ask for the PIN?+
After a restart or update it always does.
Is face unlock as secure?+
Samsung treats it as less secure than a fingerprint.