Apparently, there’s a macOS bug that if your Mac has been connected to a Thunderbolt Display for a long time, the brightness of the display can no longer be adjusted (neither by pressing the according F1/F2 keys on your keyboard nor by using the brightness slider in the display settings of the system preferences).
The simple yet surprising fix is:
- Unplug your Thunderbolt Display’s Thunderbolt cable, and plug it in again
- The display’s brightness will be adjustable again
17 Replies to “Solution: Apple Thunderbolt Display brightness control doesn’t work anymore”
OMG it worked. thank you!
Thanks for posting this. Saved my sanity.
This fixed my issue. Annoying it’s an issue, but this works!
I have tried this repeatedly and it does not work still. any suggestions?
same as mine, still doesn’t work. Try to plug and unplug but stil lthe same, the f1 and f2 still off.
Mine either (both of them) and when I connect, I don’t have ethernet through the display either. This was working perfectly 2 weeks ago.
To change the brightness of your Thunderbolt/LED Cinema Display, press CTRL and F1/F2.
Note that you must have the USB cable plugged into your laptop for this to work properly.
Worked on MBP 16″. Thanks for the cure!
Worked fine with MacBook Air 2012. Thanks for the tip.
Not working on mine – it worked yesterday – not today
mine doesn’t work as well, any suggestion?
U need to unplug the POWER CABLE of the display for a minute. Unplugging the USB isn’t enough!
I’m unable to turn my auto brightness off, f1 and f2 are not working. I tried unplugging it, any ideas?
I’m having the same problem and unplugging is not working. Any suggestions?
Damn!! it worked!! thanks a lot!!! I had headache while using this display and I think reducing the brightness will help me.
worked for me thanks
Same issue. Thunderbolt display lost brightness. Unplugged everything twice. Had to enter System Settings-Display Presets-Thunderbolt Display-Brightness.