Mac unable to set rotations of multiple monitors Having a little problem with my MacbookPro 2019-15inch-i9 (Big Sur 2020.07.08). I have two vertical monitors(ASUS VG249 1080p 144Hz)(BenQ GW2270 1080p 60Hz) and one normal monitor(DELL 2718Q 4k) set up with it, and they were working fine with a &quot;H-shape&quot; setup.
However I just found after I updated to Big Sur for a week, the setting is failed. I am able to set only 1 monitor rotated. I tried to set the second rotation after the first rotation is successful, but the this operation would reset all the settings of Display, which means the three monitors are all horizontal.
Plus, I've known it can also be a problem to Mac OS 10.15 or 10.14, I've searched it and found these problem unsolved.
Any help would be appreciated.
I've solved this problem by making a safe mode reboot.
You need to shut down your MacbookPro, hold command + R. After you get into the safe mode successfully, restart it again.
This time you get into your Mac with a normal mode, and the dual rotation of monitors is working.
A rough assumption is that a safe mode reboot may cleared some cache of the system?
Hope my solution can be helpful to you.