Hi guys,
I'm on a MacBook Pro 16" (2019) running macOS 10.15.4 Catalina. It's connected to an LG UltraFine 5K Monitor purchased directly from Apple in November 2019.
I've had the problem consistently over the past months that whenever my Mac goes to sleep and wakes up, I cannot control the brightness of the external monitor anymore: neither from keyboard, nor from the Touch Bar, nor manually under System Preferences → Displays → Brightness of the LG Monitor. The brightness stays stuck at the level it was at when the computer went to sleep. The brightness HUD shows the bars going left and right but the brightness does not change.
I can control the brightness of the MacBook's display.
The only way to resolve it is to unplug and replug the Thunderbolt 3 cable or toggle Mirroring / change resolution, that is, do something that would make the computer detect the display again.
No amount of SMC / PRAM resets, connecting the cable to other Thunderbolt 3 ports on the computer, trying a different cable, formatting the internal SSD and installing macOS from scratch, turning off Night Shift, turning off Auto Brightness, turning off Power Nap has been able to fix it. I've also tried a second display of the same model with the same results, which leads me to believe that this has something to do with Catalina. It's super frustrating.
Does anybody know if there's a solution to this problem? Many thanks.
I'm on a MacBook Pro 16" (2019) running macOS 10.15.4 Catalina. It's connected to an LG UltraFine 5K Monitor purchased directly from Apple in November 2019.
I've had the problem consistently over the past months that whenever my Mac goes to sleep and wakes up, I cannot control the brightness of the external monitor anymore: neither from keyboard, nor from the Touch Bar, nor manually under System Preferences → Displays → Brightness of the LG Monitor. The brightness stays stuck at the level it was at when the computer went to sleep. The brightness HUD shows the bars going left and right but the brightness does not change.
I can control the brightness of the MacBook's display.
The only way to resolve it is to unplug and replug the Thunderbolt 3 cable or toggle Mirroring / change resolution, that is, do something that would make the computer detect the display again.
No amount of SMC / PRAM resets, connecting the cable to other Thunderbolt 3 ports on the computer, trying a different cable, formatting the internal SSD and installing macOS from scratch, turning off Night Shift, turning off Auto Brightness, turning off Power Nap has been able to fix it. I've also tried a second display of the same model with the same results, which leads me to believe that this has something to do with Catalina. It's super frustrating.
Does anybody know if there's a solution to this problem? Many thanks.