Thank you so much! This definately helped with my issue. It was driving me crazy! I did exactly what you suggested, and the problem went away, I added the same fingerprint twice and that took care of it.
I had the same issue and find a way to fix the sensor.
1st boot in safe mode and check if the sensor works. If it does then the issue is most likely related to an application that is causing problems.
In my case the application was samsung pay. I activated the fingerprint authentication in pay and after some upgrades it started messing up with the phone.
I removed the fingermrint authetication from samsung pay (even completly removed it) and now the phone fingerprint is working like a charm.
Good to all who have the issue.
I have the similar issue with my brand new Pixel 2 XL. where the fingerprint works for sometimes after register. But after an hour it stops working. It's not able to recognize my finger. And I need to add the fingerprint again for it works. And having the same problem after sometimes.
But one of my friends suggests me this solution to get rid of this annoying issue. And It's worked for me!
I''ve been experiencing the exact same issue as most people are explaining on this thread. I had a minor emergency tonight while driving and I couldn't unlock my phone after pressing my fingers dozens of time.. and trust me, I've rebooted not long ago which does nothing.. I made sure that gestures were disabled and everything else this forum suggested.. The only thing that worked once, for a half day was going into that private mode via phone pad (*#0#*) but again - by the end of the day the problem slowly crept back into the phone and the next day it was back to the same old piece of **bleep**!
I'm fairly sure that a recent update is causing this problem or maybe an app that I added a while back and I'm pretty certain a factory reset will probably fix it, but what kind of solution is that? I have to wipe my system clean? This is unreasonable and unacceptable for such an expensive high end electronic device with obviously no attention from Samsung on this since the issue was first reported.
And just as an FYI to Samsung - I do not use the fingerprint scanner for anything but unlocking my phone.. I've never configured or tried to use it for websites or app authentication - I just want to be able to unlock my **bleep** phone while i'm driving so I can use voice controls for texts and phonecalls.
What a POS this brand is becoming.. batteries that explode, fingerprint that doesn't work, no explanation or support on this 1 item with over 35 pages of replies.. c'mon Samsung!