Thumb drive not recognized by Mac Pro.

Reset the SMC on other computers

If your Mac doesn't have the Apple T2 Security Chip, follow these steps. If you need help, contact Apple Support. 

Notebook computers with a nonremovable battery

This applies to MacBook Pro models introduced in mid-2009 through 2017, MacBook Air models introduced in 2017 or earlier, and all MacBook models except the MacBook (13-inch, Mid 2009).

1. Shut down your Mac.
2. On your built-in keyboard, press and hold all of these keys:

• • Shift  on the left side of your keyboard
  • Control  on the left side of your keyboard
  • Option (Alt)  on the left side of your keyboard

1. While holding all three keys, press and hold the power button as well.
2. 
3. 
   
4. Keep holding all four keys for 10 seconds.
5. Release all keys, then press the power button to turn on your Mac.

Sometimes an SMC Reset may bring back the USB port. Perform this action 3 time consecutively

Desktop computers

1. Shut down your Mac, then unplug the power cord.
2. Wait 15 seconds, then plug the power cord back in.
3. Wait 5 seconds, then press the power button to turn on your Mac.

Take a screenshot in the Window of Disk Utility and send it here. What does it show?