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:

  1. Shut down your Mac.
  2. Press and hold the power button for 10 seconds, then release the button.
  3. 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.