Mac keeps restarting with kernel panic "UPSB thunderbolt power on failed"

Solution 1:

I had this issue with a new MacBook Pro 2019/20 16-inch Catalina 10.15.4 (19E287)

It would frequently crash on sleep or when the screen was locked with the same error "thunderbolt power on failed" logged, now solved! (at least for my case)

The fix was to disable the extra "Thunderbolt Bridge" service (used for direct Mac to Mac transfer over thunderbolt cable) in the Network Settings

System Preferences > Network > Thunderbolt Bridge (right-click > Make Service Inactive)

Note: the screenshot says "make active" because I already disabled it. Yours would say "make inactive"

After that, no more random crashes/shutdowns on lock screen or sleep.

Solution 2:

I have had the same issue. Tried Beta and that made the problem only worse. I got the fix by resetting NVRAM and SMC.

To do so, shut down your Mac, then turn it on and immediately press and hold these four keys together: Option ⌥ + Command ⌘ + P + R

Please try to reset yours to see if it resolves your issue.