M1 Mac Mini does not activate connected monitors, some owners complain

Some customers who have purchased an M1 Mac mini are experiencing an issue that causes the machine to fail to wake up a connected third-party monitor from home.

This is not a problem that is affecting all doM1‌ ‌Mac mini but owners, but there are numerous complaints about the MacRumors Apple Support Forums and Communities since November, when the “Mac mini” was first launched. MacRumors the gooimac reader explains:

My ‌M1‌ (8gb / 256) ‌Mac mini‌ doesn’t seem to want to wake my monitors after sleeping. I tried with 2 different monitors with 2 different HDMI cables with the same thing occurring on each one. I am currently using only one at a time. I also noticed some pink squares / graphical flaws in the Big Sur startup / login screen (with the colored background, not the black and white boot)

MacRumors reader Mike, who sent us an email on the subject, saw the same problems.

I have a new Mac Mini ‌M1‌ with 16 GB of RAM running Big Sur 11.2.3 and whenever the computer and the screen go to sleep, the computer will not be able to wake up the screen.

In fact, I get “No Signal” displayed on the screen after the Mini wakes up, so technically the computer wakes up the monitor, but is unable to send a video signal. The screen is a 34 “LG Ultrawide 4K Thunderbolt. It wakes up well with my MacBook Pro 2018, so there’s nothing wrong with the screen itself.

The only way to get the Mini to send a signal to the monitor is to disconnect and reconnect the Thunderbolt cable. Sometimes, repeatedly. Obviously, this is not an ideal solution.

This problem appears to be affecting a wide variety of monitors that connect via Thunderbolt, HDMI and DisplayPort adapters, but there are also many people who are not experiencing any problems.

It is unclear what the problem is, but Apple is investigating a ‌M1‌ ‌Mac mini‌ screen problem that causes strange pink squares to appear on screens connected to one of the machines.

Apple is aware of the problem and there may be a fix in progress in a future update. One solution for now may be to disable the feature that puts the ‌Mac mini‌ in hibernation, but this is not ideal. The other solution is to disconnect and reconnect a monitor that is not responding after a ‌Mac mini‌ wakes up from standby, but this is also an inelegant solution. There appears to be no other fix available at this time.