M1 Mac Mini, Displays wont turn on after wake from sleep

I have the same problem but only have 1 monitor. It is a DELL3007WFPHC 30" Display. It is rather random indeed. Waited many years to get a new mac...seems as if I should have waited 1 more...

It's

JideTech KVM Switch 2 Displayport 4K @ 60Hz 

Please keep in mind, it's just a workaround. Apple should fix this bug.

thank you for the comment. have you reported yourself to Apple Support yet? I hope every one of us who has this issue should report so they can build up a case that is more prioritized

I have the 16gb, 500gb M1 and Dell U2720 connected to HDMI. It sometimes doesn't recognize the connection too from sleep or sometimes on startup. Weird annoying bug.

Problem is, a hardware problem doesn't explain why the wake issue also happens virtually using "Share Screen..." in the Finder.

I have a similar issue. Only one display connected - Apple Pro XDR. Sometimes, even if the screen wakes up, I'm unable to sign back in as the mouse and keyboard are not recognised. Briefly pressing the power button seems to resolve the issue. Also unable to have my Apple Watch unlock the Mac even though security settings say it's enabled.

For the time being, until my LG 32 inch Ergo arrives, I have an Acer K227HUL display connected to the M1 mini via HDMI. If the screen saver is present, either magic keyboard, or magic mouse 2 will wake it. If black screen after screen saver has ended, then only a single click from the magic mouse 2 will wake it after several seconds of delay.

These may be issues resolved in the next Big Sur update.

Well, if you really disabled sleep, it won't need waking. So that would point to an issue with your LG (check settings). If you didn't disable sleep, do it by going to System Preferences > Energy Saver > Prevent computer from sleeping. Good luck.

The box I have checked (since yesterday) in Energy Saver says "Prevent computer from sleeping automatically when the display is off." That's the only box that has to do with sleep that I can find. I assumed "sleeping" had to do with the computer and not the display, meaning certain systems in the computer would not "sleep."

Also, even if I use a hot corner to enable Lock Screen when I step away from the computer for 10 minutes or so, the Lock Screen will eventually "sleep" the monitor - even though I have "Turn display off after" set to 3 hours. So the problem persists anytime you just want to lock your screen to step away from your desk.

However the problem I have persists even on startup of the new computer. For example, last night I shut down the computer completely just to leave it off and not worry about the problem overnight. This morning when I powered up, the monitor would not wake up or I assume the Mac mini did not recognize the monitor. I unplugged the Thunderbolt cable several times but it still didn't work. Finally I did another hard reboot (pressed the power button) and it finally came on (with a weird green screen on power up).

So I don't think the problem is just a matter of the "sleep" setting in Energy Saver menu.

Well in that case, it's definitely LG. Too bad because their support socks. Try fiddling with the monitor settings, might get lucky...otherwise replace or live with it, I wouldn't count on a "fix" from Apple (if you go the replace way, avoid wide screens).

What about my post leads you to believe it's definitively the LG monitor? I have used this monitor with no issues with my 2019 16" MacBook Pro both with Catalina and for the past month with Big Sur. There are no energy settings enabled on the monitor. Seems to only be an issue since adding the Mac mini last night. With all of the posts mentioning similar display problems it seems odd that simply because I have the sleep button checked it would definitely be my LG monitor.

EDIT: Just swapped over to my MBP and went through all of the Lock Screen/sleep etc procedures and every single time my monitor woke up with a spacebar tap - seems to be a problem with the Mini, which unfortunately I think will be going back.

I had the same problem with multiple monitors on my 2018 Intel Mac mini (never solved to this day), but, wait, my 2020 M1 Mac mini does *not* have this issue (monitor connected via USB-C to VGA as were the Intels). Go figure!

You haven’t posted details so unable to comment further. You can anyway always manually switch monitor off.

Looks like an M1 issue assuming your monitor isn’t dongled, dualed or otherwise setup differently. Good luck.

Well, it’s monitor and dongle dependent. My single HDMI Dell has worked without a hitch from day 1 late 2018. I should add that I’m on a mission to rid the world of dongles, DVI-capable monitors, eGPUs and crowded USB hubs, something I suspect Apple is too. IMO, anyone using these are powerless users who like more to fidget endlessly with cables, backups, restores, recoveries and the like than getting on with real work.

I don’t think Apple Support will help you, but you’ll definitely get more sympathy than my post here. Nonetheless, I’ll let you go through the hoops with them. If you’d rather not, I recommend you ditch the dual monitor config and stick to HDMI until dongle-proof USB 4 monitors start rolling out, which should happen late 2021. Good luck!

The M1 Macs have a completely new restart system. You have to hold the Power button down until it enters "startup mode". It'll show "loading startup options" and then there's a whole new system of menus and options.

https://eclecticlight.co/2020/11/28/startup-modes-for-m1-macs/