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

I have exactly the same issue. Single monitor, via HDMI connection, does not wake up from sleep. Fortunately, knock on wood, my monitor will connect if I turn it off and back on again. Whatever trigger the Mac mini is supposed to send out, to wake the monitor, does not seem to be working.

That doesn't work. If you disable sleep, you have to turn off the monitors manually, and when you turn them back on, the configuration and arrangement are wrong. No matter what you do, you always have to change the configuration to get the images to work properly. This is probably a software problem, maybe drivers, but it is something we can't solve without Apple's help. Support told some guys that Apple is working on it, but so far no news.

That shouldn’t be necessary if you have the monitors switch off by timer (see trevoz’s post below). If it is, it’s to do with your dongles and your monitors, with the oversized Samsung most likely suspect. I doubt you’ll get a fix from Apple, good luck anyways.

UPDATE - I received my new LG monitor today, as well as new Logitech MC Keys for Mac. With that new combination, pressing a key on the keyboard is waking the monitor from sleep without issue. I have continued using HDMI to HDMI rather than USB-C, as I wanted to leave those ports open.

I have a similar issue. New M1 Mac Mini with 2 Samsung displays (HDMI & USB-C).

Both screens enter a flicker mode after a restart. It also does this after the displays have turned off by the Mini inactivity timeout. I have to disconnect one display from HDMI and restart the Mini. I then reconnect the second screen to HDMI.

My "fix" was to disable the screen saver. I also set the Energy Saver "Tuen off Display" to never. I just avoid restarts.

I also changed my background from slideshow to a single photo that doesn't change.

Another separate issue I discovered while trying to fix this -

The startup keys do not work during restart. Specifically "command R".

I have tried 4 different keyboards and replaced both video cables.

I'll be hoping for an update fix.

Yeah I'm experiencing similar issues with my M1 MacBook Pro. Except it's not when the computer goes to sleep, it's simply when it shuts off the displays. When I tap the keyboard or trackpad, the MBP screen comes back fine but the external display does not. Even disconnecting/reconnecting the display does not help. I have to perform a full reboot. I can consistently duplicate it with both HDMI & DisplayPort. My options are either shut it down every time I'm done with the computer, or disable the system from shutting the display off and rely solely on the screen saver. It does consistently come back with every reboot though. My previous Intel Mac mini had a lot of reliability problems with external display. The frustrating thing is that consistent "it just works" display support is one of the reasons I switched to Mac 18 years ago.

I think you may be missing the underlying issue here. There are people replying to the original post with issues on other M1 Macs, not just the mini. Clearly there's an issue here that's not specific to the Mini and has not been an issue with the same monitors and adapters on non-M1 macs.

This is the Mac mini forum - posting about other Macs is not very helpful.

In any event, there were very similar. if not identical. issues with the 2018 Mac minis (plenty of threads in here) which I also experienced. For me, the M1 Mac mini resolved my monitor not waking issues (Apple USB-C to multiport adapter for my VGA monitor) once set to turn off the display after x minutes and prevent the computer from sleeping while display is off. No combination currently works for my two Intel 2018 Mac minis other than not letting the monitor sleep and also not letting the computer sleep.

Previous Mac minis all the way back to 2006 did not have these issues (I have at least one of each except the 2014 model).

When my M1 mini first arrived, I had it connected HDMI to HDMI on a Alienware AW2518H 1080p gaming monitor. With that configuration, whether I let the whole system sleep, or just the monitor sleep, it would not return to life without using the monitor power button to turn it off and back on again.

Once my LG 27UN850-W monitor arrived, still using HDMI to HDMI (using their in-the-box cable), it works perfectly. The system goes to sleep and will then wake up with the press of a key on the keyboard. My prior HDMI cable was a quality 8k cable, so I doubt that had any bearing on the problem. For me at least, the issue seems to have been the monitor as opposed to the Mac mini.

I got my M1 mini a few weeks ago and have a 38 inch LG UW Monitor connected to the USB-C . I haven't encountered any flickering issues but when the computer goes to sleep . There's no display when it wakes up .

I either have to switch to the other USB-C port or HDMI to get the display working.

This did not happen with my 2018 Mac mini.

Turning Sleep OFF does not fix the issue.

I had this issue with my 2018 Mac mini, my 2020 m1 Mac mini, and my 2019 MBP 16". Seriously Apple, I know it isn't exactly an iPhone (much larger market), but how about addressing this issue... it has been constant for years.

Is there a common denominator across the 3 different machines? Such as the same monitor for each? My M1 Mac mini would not wake up with my old monitor but now works perfectly with my new monitor. Same machine, different monitors, problem solved.

The same monitor was used between the 2018 MacMini (i5 Model) and 2019 MBP16" (base model) and then I changed the monitor out (similar/updated model) and used that between the 2019MBP16" and 2020 MacMini M1. The monitor I have with the 2019MBP16" and MacMini M1 is the LG27UK650_600 (27" 4K Monitor). Oh, also had the 27" Alienware gaming monitor hooked up to the previous two machines (non-M1)... Also, at one point had a 13" MacBook Air 13" (entry level processor)... that was having issues too with the monitor not coming on out of standby.

Similar problem. I run two Dell 4k monitors on a new M1 Mini. The primary monitor w/dock will behave as expected after sleep or upon first opening in the morning. The second monitor has to be shut off and on to wake in the morning and, also, after some period of time (I haven't experimented) when in sleep. It will wake from sleep if it hasn't been in for very long. Initially, the second monitor couldn't detect an image due to my 3rd party HDMI to USB-C adapter not being supported (not a problem for my 2019 mini). I purchased the Apple Multi adapter to solve the undetected image problem but now have the apparent sleep problem...

Same family then. I am using the LG 27UN850-W. My Alienware monitor would not wake up but my new LG does. The only other variable is that when I changed out monitors, I used the HDMI cable that came with the LG monitor. Previous to that I was using a high quality 8k HDMI cable, so would not expect that to be a contributor, but you never know. I'm just happy as is good now and my Bluetooth Logitech keyboard and mouse are consistent, so far, with no connection issues. Knock on wood, with the monitor situation resolved, I am not experiencing any of the issues that others are reporting.