The new Mac Mini with Apple's fantastic M1 chip is one of the most affordable Macs on the market right now. However, this does not mean that it is completely immune to problems, and some owners of the mini computer have complained that attached displays cannot be woken from hibernation when necessary.
For example, the MacRumors forum user, gooimac, reports the following experience: "My M1 (8 GB / 256) Mac mini doesn't seem to want to activate my displays after going to bed. I have 2 different displays with 2 different ones Tried HDMI cables with the same thing on each. I only use one at a time. I also noticed some pink squares / graphical errors on the Big Sur startup / login screen (with the colored background, not the black and white startup) . "
Other people have had the same problem, such as Pearsnet posting comments on Apple's own Support Communities forums. However, the cause of the problem is still unknown. Pearsnet's issue was addressed by changing a Mission Control setting in System Preferences. However, it is not clear whether this would work in every case.
According to MacRumors, the bug is not limited to one type of Mac mini monitor as it appears to affect all displays with DisplayPort, Thunderbolt, and HDMI ports. Apple is said to be aware of the glitch but hasn't issued a fix yet, and the only solutions are currently unofficial. If you're affected, you can turn off the feature that puts your Mac Mini to sleep, or unplug and reconnect the affected monitor. However, neither is particularly practical.
It's worth noting that not all Mac Mini users are affected. I own a Mac Mini with an M1 chip and have never seen my attached display fail to activate. Hence, it is unlikely to be a bug that is common to all Mac Mini owners. However, I did experience the pink squares error reported by gooimac – another issue that Apple did not fix.
However, if you own one of Apple's tiny desktop computers, be careful not to fall prey to the sleep / wake bug. While it won't completely ruin your Mac Mini experience, it is still irritating.