Oneplus 2 - Cannot record fingerprint

[AC Question]

Initially I set up fingerprints and all was well, then starting the phone using my finger got more and more hit & miss until eventually I deleted the fingerprint to start again.

However now I cannot record a fingerprint. I've cleaned the sensor and washed & dried my hands, but the furthest I get is 18% before I get a vibration lifting my finger as well as when the sensor records it, followed by a 'too fast' message, followed by progress back to 0%, and so on.

If anyone tells me to clear the fingerprint data cache, please also tell me how. 'Fingerprint' doesn't appear in Setting, Apps.

 

[belodion]

Look in Settings, Security.

 

[cats_five]

Look in Settings, Security for what? Fingerprints? Not there.

The only reference to fingerprint there on my phone is enabling fingerprint unlock, which is disabled since I don't have any fingerprints registered. When I try to register one I'm back to the double-vibrate problem, except I now realise it simply does it twice sometimes, it's not to do with when I lift my finger.

It's up-to-date - Android 5.1.1 and Oxygen 2.2.0.