I have a new Mac Studio (2022) with the Apple M1 Ultra chip. I use two Studio Displays. Today, our power went off and the UPS tripped shutting down before I could take action. When I got it reset, one of my two Studio Displays was much dimmer than the other. I tried changing Thunderbolt cables, changing ports, restarting multiple times, using settings but nothing worked.
I called Apple support. The first person was helpful, but didn't resolve the problem. They got Derrick from tech support on. He checked in the System Report and didn't see a firmware number for one of the Studio Displays. THE FIX:
- Unplug the Thunderbolt (or USB-C) cable.
- Unplug power for the Studio Display monitor that wasn't working correctly. Leave unplugged for at least a full 2 minutes.
- Reconnect the Thunderbolt cable.
- Power on the Studio Display.
The entire time, my Mac Studio was left running. It worked and both monitors are functioning normally. The System Report shows a correct 15.5 (build 19F77) firmware for both monitors again.
ALL IS GOOD and Apple Support did an outstanding job.