M1 Mac Mini Won't Wake Connected Displays, Some Owners Complain
This is not an issue that's affecting all M1 Mac mini owners, but there are numerous complaints on the MacRumors forums and the Apple Support Communities dating back to November when the Mac mini was first released. MacRumors reader gooimac explains:
My M1 (8gb/256) Mac mini doesn't seem to want to wake my displays after its been sleeping. I have tried with 2 different displays with 2 different HDMI cables with the same thing occurring on each one. I am currently only using one at a time. I also noticed some pink squares/graphics glitches on the Big Sur boot/log in screen (with the coloured background, not the black and white boot up)
MacRumors reader Mike, who emailed us about the issue, has seen the same problems.
I have a new Mac Mini M1 with 16 GB of RAM running Big Sur 11.2.3 and every time the computer and screen go to sleep, the computer will not be able to wake the screen up.
Actually, I get "No Signal" displayed on the screen after the Mini wakes so technically the computer wakes the monitor but it fails to send a video signal. The screen is a 34" LG Ultrawide 4K Thunderbolt. It wakes fine with my 2018 MacBook Pro so there's nothing wrong with the display itself.
The only way I can get the Mini to send a signal to the display is to unplug and replug in the Thunderbolt cable. Sometimes repeatedly. Obviously, this is not an ideal solution.
This issue appears to be affecting a wide range of displays that connect over Thunderbolt, HDMI, and DisplayPort adapters, but there are also plenty of people who are having no issues at all.
It's not clear what the problem is, but Apple has been looking into one M1 Mac mini display issue that causes strange pink squares to appear on displays connected to one of the machines.
Apple is aware of the issue, and there could be a fix in the works that's coming in a future update. One solution for now may be to disable the feature that puts the Mac mini to sleep, but that's not ideal. The other solution is to unplug and replug in a display that's not responding after a Mac mini wakes from sleep, but that too is an inelegant solution. There appears to be no other fix available at this time.