MP 1,1-5,1 can't change the brightness since yesterday !!

[mohnumber7]

hello, since yesterday, I can no longer change the brightness of my screen with the F2 and F3 keys on my apple led cinema 27, as you can see on the photo, rather bizard, how to fix this problem? thank you

 

[EugW]

Unplug and replug USB, unplug power from monitor and plug back in, and restart Mac.

 

[minifridge1138]

Kill the corebrightnessd process. It will restart itself.

Option 1 -
Launch Activity monitor. Sort by Process Name. Find 'corebrigthnessd' and highlight it. Click the 'stop process' button. You'll be asked for an admin's username and password.

Option 2
Warning - terminal commands ahead. If you aren't comfortable with the a shell, turn back now.

# Run this to get the process id of the process - you want the number in the 2nd column (in this case 121, but it could be anything):
Command:
ps -ef | grep corebrigthnessd

Output:
0 121 1 0 Sat04PM ?? 0:00.52 /usr/libexec/corebrightnessd --launchd
503 7444 7436 0 10:49AM ttys000 0:00.00 grep corebrightnessd

# Kill the process - VERY CAREFUL WITH THIS COMMAND!!!
Command:
sudo kill -9 121

 

[mohnumber7]

THANKS !! the first option worked , thanks man