Apple - Cannot set up Touch ID, unlock System Preferences, or reinstall Big Sur [2020 Intel MBA i3]
Answering my own question, but... resetting the SMC (as explained here https://support.apple.com/en-ca/HT201295) ended up doing the trick for me.
The fix for me was actually the steps before resetting the SMC, so I didn't need to do an SMC reset. Here are those simple steps:
- Shut down your Mac.
- Press and hold the power button for 10 seconds, then release the button.
- Wait a few seconds, then press the power button to turn on your Mac.
Source: How to reset the SMC of your Mac by Apple
Worth noting I did first remove all existing Touch ID fingerprints from my Mac before doing this.
UPDATE: It's also worth remembering that Touch ID is disabled for the first login after a shutdown
Encountered the same issue w/ System Preferences. An SMC reset fixed.