Solution: Apple Thunderbolt Display brightness control doesn’t work anymore

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:

  1. Unplug your Thunderbolt Display’s Thunderbolt cable, and plug it in again
  2. The display’s brightness will be adjustable again

 

(credits: https://forums.macrumors.com/threads/thunderbolt-brightness-control-settings-gone.1254406/)

20 Replies to “Solution: Apple Thunderbolt Display brightness control doesn’t work anymore”

      1. 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.

        1. 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.

    1. i found a solution: plug in the usb connector along with the thunderbolt connector!! if you only plug in thunderbolt, it doesn’t allow you to control brightness. If you do, you can control brightness.

    1. plug in both usb connector and the thunderbolt connector to be able to control brightness on the thunderbolt display. If you have an apple keyboard, you can even adjust brightness from there.

      Also, originally i had my mouse plugged into my mac mini, but realized i could plug it instead into my Apple magic keyboard.

  1. Damn!! it worked!! thanks a lot!!! I had headache while using this display and I think reducing the brightness will help me.

  2. Same issue. Thunderbolt display lost brightness. Unplugged everything twice. Had to enter System Settings-Display Presets-Thunderbolt Display-Brightness.
    Working now!
    Thanks!

  3. for me, I needed to plug in the USB cable. Because the thunderbolt display works with only the thunderbolt cable plugged in, but if you want anything other than max brightness, you have to plug in the USB cable too.

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