If you troubleshooting a Touch Bar that has stopped working on an Late 2016 MacBook Pro, where the Touch Bar is completely black, try these steps to restore functionality:

  1. Create a new local user account (to use temporarily for steps 2-4)
  2. Reset the NVRAM
  3. Log in as the new user
  4. Log out then log in using the primary account
  5. Assuming the Touch Bar is working, delete the user account you created in step 1

I’m not quite sure why creating the new account and logging in with it after a NVRAM reset is necessary, but this process is what Apple support is walking people through who are experiencing this problem… and many people have reported it works.