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

Well, I have just installed Big Sur 11.6 update. Not sure yet if it's solve the monitor not waking up problem but I get theimpression that it has introduced a new one... when I wake the computer, application windows sometimes seem to have moved from the screen they were on when I put the computer to sleep - and I have to move them back to the monitor they are supposed to be on.

I have similar issue. Only obvious difference to OP is that I do have only one external display (LG TV) connected to my Mac Mini (2018), Big Sur 11.5.2 .

Typically it won’t turn on display after going sleep (sometimes even after a few seconds) in approx. 25% attempts.

The most strange observation is that if I exit Safari before Mac goes to sleep, this issue does not occur anymore, at least 20 times in a row.

I have a Mac Mini 2018 model and 4 (FOUR) different Dell monitors that I've tried one at a time or in multiples. This happens intermittently with all of the Dell monitors in all situations. Sleep setting are irrelevant. This needs to be fixed! I'm reading comments from user with the same issue from a few years ago! Unacceptable. Apple has something like $250 BILLION dollars in CASH in the bank. They can't figure it out?

Apple is going crazy trying to fix this problem, but until they realize it happens with NO monitor, using "Share Screen" to another Mac and the WINDOW locks up exactly like a physical monitor, then they will never figure it out.

I have a very similar problem. I have a new generation M1 Mac Mini connected to a new LG HDR QHD Monitor via USB-C cable, and the mac mini does not switch on this monitor at least half the time, and perhaps even most of the time. I try everything, and nothing works until I physically unplug the USB-C cable and plug it back in. It will only then come on to my home screen.

I have the same problem but slightly different.... Thank god I thought I was going mad!!!

I have just bought a second 2018 Mac mini connected it to ONE Samsung 65" tv. Everything works fine but if it goes to sleep at night it won't come back on with the press of a key or the movement of the mouse. I have to reset the Mac mini for it to boot again????

I am just using a HDMI lead, which I know works perfectly as it was on my 2013 Mac mini setup for years and I never had this issue.

I have tried turning sleep off but, nothing!! It simply says on the screen that the tv cannot find the source and shows a powered off button.

Im on Monterey 12.0.1.

Is there a solution to this as I have only switched my old Mac mini to a newer version and now have problems??

de-selecting "Displays have separate Spaces" doesn't work for me (I did log out and log in). USB C port display (connected via KVM switch) simply doesn't come on till I unplug the USB C and reconnect. Windows and Linux machines on the same KVM switch have no problem and work perfectly.

I've just updated to 12.1 too.

It's not enormously better though it is more successful at recognising the screen on the USB-C port and bringing it up.

However, there's often a delay and it always relocates all my open windows to the other screen. I work with a lot of windows open so this is a total productivity killer.

I wonder if the relocation of windows happens when I switch away from this Mac to another machine on the KVM switch rather than when when I switch back and the screens come on again (i.e. there's a timing difference when the screens go off that causes the OS to think one screen is gone and the other still connected). Whatever the cause, when I return to this Mac the windows are all moved. It sucks!

I have the same thing. But before the screen goes out, there are any noises on the screen like an old TV that does not catch the channel. All accessories are authentic from apple. Cables and adapters from apple. Sleep outages also fail. This basically happens after a long night. I tried everything, but the problem is constantly haunting me. And I thought apple produces a quality product. Another nuance! Before touching the aluminum case, I feel statics and then this problem occurs

My Mac mini has had several problems

1) I turn on WiFi and the monitor (2 of 2) connected to a USB-C hub via HDMI goes blank. Now have to use ethernet.

2) Waking from sleep is hit and miss! Sometimes it works and sometimes it does not. I have to unplug/replug the monitors.

3) My monitors get flipped (L<->R) sometimes when they do come out of sleep.

4) Cannot use cordless mouse/keyboard the connection is intermittent. This same keyboard mouse worked on my old MacMini (2012) for years. Tried 3-4 different combinations and all exhibited the same behavior. Now use wired mouse/keyboard (Same wireless that does not work on Mac mini works fine on work laptop (Windows).

5) Sometimes the mouse (wireless/wired) is not responsive to dialog boxes or System Preferences. Can click on close button at top of window but not any selection within box. Only way to fix is reboot!

IMO this Mac mini is a prototype at best and is the first Apple product that is really a POS. I've been using Macs since the original G3 iMacs. iPhones since 4S, Apple TV (4 different) since original PPC version. Apple really laid a turd with this!. (I love the M1, just not the supporting HW).

When you have two monitors but only one wakes up from sleep:

System Preferences / Mission Control / De-Select “Displays have separate Spaces” / Log Out / Log In

Yes. Many of us are having big issues with the new Mac mini and multiple monitors. They say that Apple is looking into this. https://discussions.apple.com/thread/252072263

Disable sleep.

Not necessary, disable sleep, be happy.