I had the same problem as everyone else and finally decided to try and fix the problem. Under my device manage I had the little yellow triangle that signaled an error of some sort. Synaptics WBDI SGX was the driver name. Tried everything listed in the various replies of this thread without any luck. I even tried updating the drivers and got the message that they were already up to date. Finally I decided to try a different update that I had dismissed previously and it worked instantly!
What I did that finally worked was this:
windows + X
click on device manager
right click on the driver under Biometric Devices (If it is hidden click view and then show hidden devices to see it)
click update driver
click the SECOND option which says BROWSE MY COMPUTER for drivers. (The first option just told me the best drivers were already installed.)
Click let me pick from a list of available drivers on my computer
Click the driver listed. (I only had one listed and it was the same as the one I was trying to fix Synaptics WBDI SGX)
Click next
Let the install complete.
At this point my yellow triangle vanished.
I then went straight to my sign in options setting screen (which you can type in the search bar for easy access) and when I clicked windows hello fingerprint it said it was ready for me to use! No restart required.
I share this in the hopes that it helps someone else who had no luck with any of the other methods listed.