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Same problem with my 5120x1440 Samsung CRG9. Tried different cables and it still doesn’t wake form sleep.
For me it is fixed by setting DisplayPort version to 1.2 but then it uses chroma subsampling instead of rgb (so blurry texts/colors).
 
Same here. Problem persists after upgrading to 11.2. Hugely disappointing. USB-C -> Belkin dual link dvi adapter -> Apple Cinema Display 30”. Display not waking up from sleep.
I know, I had a tiny bit of hope that 11.2.1 would surprisingly fix the sleep/wake issue — but WRONG! (I installed it yesterday evening and tested it with fingers crossed) — at least Apple is getting the updates out there fairly quickly...
 
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This is likely to be a hardware issue connected with low level of HDMI sygnal, but fortunately solvable, though still irritable. I like to think I may have figured that out and I hope that this will help you lot. one day, I was watching Netflix when I was called off on an errand, after which I found my Mac Mini (M1) asleep. Normally, it would on occasion unlock with my iWatch, but then again sometimes I would get the haptic reaction on my watch and nothing would happen, and I had to hard-reboot it, which obviously I hate, because of data corruption issues that may ensue. That one time, however, I discovered that the Mini did wake up, because I could start and pause Netflix. While this may not be an issue on Apple monitors, apparently the signal was too week for my 27" widescreen Samsung display. It was getting some signal, but apparently not enough to wake it, and it kept swotching between HDMI and analogue (VGA). The reason why I think I think it was generating HDMI signal as opposed to no signal is that when there indeed is no signal, the display says check cable, no signal message, which it wouldn't on all previous instances.
NOW FOR THE SOLUTION: I disconnected my iWatch charger, that was permanently hooked to the Mini for convenience. This seems to have worked like a charm (fingers crossed), and I can only guess that the charger was draining just too much power for the HDMI signal to conform to the level needed to wake my display.
 
This is likely to be a hardware issue connected with low level of HDMI sygnal, but fortunately solvable, though still irritable. I like to think I may have figured that out and I hope that this will help you lot. one day, I was watching Netflix when I was called off on an errand, after which I found my Mac Mini (M1) asleep. Normally, it would on occasion unlock with my iWatch, but then again sometimes I would get the haptic reaction on my watch and nothing would happen, and I had to hard-reboot it, which obviously I hate, because of data corruption issues that may ensue. That one time, however, I discovered that the Mini did wake up, because I could start and pause Netflix. While this may not be an issue on Apple monitors, apparently the signal was too week for my 27" widescreen Samsung display. It was getting some signal, but apparently not enough to wake it, and it kept swotching between HDMI and analogue (VGA). The reason why I think I think it was generating HDMI signal as opposed to no signal is that when there indeed is no signal, the display says check cable, no signal message, which it wouldn't on all previous instances.
NOW FOR THE SOLUTION: I disconnected my iWatch charger, that was permanently hooked to the Mini for convenience. This seems to have worked like a charm (fingers crossed), and I can only guess that the charger was draining just too much power for the HDMI signal to conform to the level needed to wake my display.
This is very unlikely because M1 Mac mini only drains a fraction of what the x86 needed, whilst retaining the same power source.
 
The solution for my setup - M1 Mac mini and LG 38WN95C-W display - is pretty simple.
I connect them with both TB3 and HDMI cable.
The LG display has hardware controls that allow me to change its input signal.
So I can switch between TB3 and HDMI.
So far, when the one actively connected to the M1 doesn’t wake up the display, switching to the other input has always worked.
I can live with that. :cool:
 
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The solution for my setup - M1 Mac mini and LG display - is pretty simple.
I connect them with both TB3 and HDMI cable.
The LG display has hardware controls that allow me to change its input signal.
So I can switch between TB3 and HDMI.
So far, when the one actively connected to the M1 doesn’t wake up the display, switching to the other input has always worked.
I can live with that. :cool:
I tried your connections today, but didn’t get that lucky — I had more issues with the resolution automatically changing from scaled to standard without anything I did. I couldn’t get the display to wake up when I would change the monitor settings back and forth between HDMI and USB-C. For now, just changing the DisplayPort setting to 1.2 from 1.4 within the monitor settings solves my wake/sleep issues — so I guess I’m stuck w/ this setting for now.
 
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I have a LG 38UC99 with a Mac Mini M1 1TB / 16GB and found that my Display is waking up just fine once I connect the display through my USB-C Hub (HDMI and USB-C)
Not ideal and truly a design flaw but something I can live with since I use a Hub anyway.
 
My M1 (8gb/256) Mac mini doesn't seem to want to wake my displays after its been sleeping. I have tried with 2 different displays with 2 different HDMI cables with the same thing occurring on each one. I am currently only using one at a time. I also noticed some pink squares/graphics glitches on the Big Sur boot/log in screen (with the coloured background, not the black and white boot up)

I am going to leave it with the display set to never sleep for now to see if anything is different after leaving it for a while.

Any one else having similar issues? I don't have a USB-C to HDMI or DisplayPort to try currently.
My M1 mac mini has this problem. Apple Case Number: 101297959391 Updated to 11.2.1 and it still does it. I am trying to find a way to tell the computer to reboot short of holding the power button down until it powers off then powering it back on.
 
I tried the thunderbolt LG32UL950 and it was a nightmare with the M1 MBP. It often would cause a kernel panic in the Mac when waking from sleep. I switched to DP 1.2 and that helped but even then it took like 20-30 seconds to wake everything. Switched back the the LG 27UN850 USB-C and its rock solid. I think the Apple M1ss combined with LG Thunderbolt monitors can be pretty problematic. Hopefully a fix soon. BTW I dont see much benefit going from a 4K 27 to 32 so im ok with the 27 for now.
 
I tried the thunderbolt LG32UL950 and it was a nightmare with the M1 MBP. It often would cause a kernel panic in the Mac when waking from sleep. I switched to DP 1.2 and that helped but even then it took like 20-30 seconds to wake everything. Switched back the the LG 27UN850 USB-C and its rock solid. I think the Apple M1ss combined with LG Thunderbolt monitors can be pretty problematic. Hopefully a fix soon. BTW I dont see much benefit going from a 4K 27 to 32 so im ok with the 27 for now.
I have come to the same fact, I just waited too long I guess past the return date for my 32UL950. It’s really frustrating as when I researched which monitor to purchase, there weren’t that many posts on this particular display with issues, now there are. I really wanted the additional screen real estate space w/ a 32”. I came from two 27” displays and didn’t want to back to that route. I’d have a hard time selling this display and get my money back out of it now I’d say, even though it real produces a great picture. I’ve not had any issues w/ DisplayPort setting at 1.2 currently. Do you feel there will be a fix coming from Apple?
 
I have come to the same fact, I just waited too long I guess past the return date for my 32UL950. It’s really frustrating as when I researched which monitor to purchase, there weren’t that many posts on this particular display with issues, now there are. I really wanted the additional screen real estate space w/ a 32”. I came from two 27” displays and didn’t want to back to that route. I’d have a hard time selling this display and get my money back out of it now I’d say, even though it real produces a great picture. I’ve not had any issues w/ DisplayPort setting at 1.2 currently. Do you feel there will be a fix coming from Apple?
Its really up to Apple on a fix. There is no more screen real-estate with a 32 4k vs 27 4k. I actual prefer the 27 as its sharper due to smaller pixels. Id consider 32 again but want 5k min and apple needs to fix the thunderbolt issues.
 
Iv'e been having this issue as well since day 1. Dell HD via HDMI, some days it works somes days I have to do a restart to get a video signal. No issues with my 2018 Mini.
 
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I bought M1 Mini back in December and had Dell P2419HC monitor with this issue through USB-C. I returned it after a week.
I sold that display and bought Dell U2520D with USB-C DisplayPort and wanted to try again so I bought a new Mini and it works perfectly with 11.2.2 update. I'm using Apple's 0.5m Thunderbolt cable. It wakes up every single time from sleep or restart.

It's YPbPr but text and image is very clear so I don't care. I suppose in future updates they will have new display profiles so it won't be purplish if I switch to RGB.

Bluetooth issues seem to be gone too, no drops or anything for the last 3 days..
 
Just to add to this unbelievable M1 video output mess: Just yesterday the issue seemed to be getting even worse, as (for the first time) I needed to do a hard reboot to get the machine to send a video signal to the monitor at my office after sleep. Unplugging/re-plugging the HDMI cable multiple times had absolutely no effect. Rebooting worked instantly. But doing hard reboots daily is not a solution. I’m rather shocked that Apple has let this issue slip through quality control, whether it’s hardware or OS related.
 
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My M1 (8gb/256) Mac mini doesn't seem to want to wake my displays after its been sleeping. I have tried with 2 different displays with 2 different HDMI cables with the same thing occurring on each one. I am currently only using one at a time. I also noticed some pink squares/graphics glitches on the Big Sur boot/log in screen (with the coloured background, not the black and white boot up)

I am going to leave it with the display set to never sleep for now to see if anything is different after leaving it for a while.

Any one else having similar issues? I don't have a USB-C to HDMI or DisplayPort to try currently.
I have exactly the same issue. I have found one possible work-around. I use blutooth mouse and keyboard. When I plug in my keyboard to charge it, it is connected to the USB port in the minimac. When the keyboard is plugged in, it wakes the computer just fine. When I fist got my minimac, it would lose the blutooth connection to the mouse periodically. This hasn't happened since some of the Big Sur updates. However, I am suspicious that this is a blutooth connectivity problem. The wired keyboards seem to wake the mini without issue.
 
I have exactly the same issue. I have found one possible work-around. I use blutooth mouse and keyboard. When I plug in my keyboard to charge it, it is connected to the USB port in the minimac. When the keyboard is plugged in, it wakes the computer just fine. When I fist got my minimac, it would lose the blutooth connection to the mouse periodically. This hasn't happened since some of the Big Sur updates. However, I am suspicious that this is a blutooth connectivity problem. The wired keyboards seem to wake the mini without issue.
Hi :) I don't think it's a bluetooth issue. When I wake the computer after sleep, my Apple Watch actually unlocks it automatically as expected – but the screen doesn't wake up.

EDIT: That being said, I still have bluetooth issues every single day. So, I always have a USB mouse and keyboard plugged in as a backup. Crazy. I really don't get why this product was released, when it's obvious that multiple show stopping issues persist.
 
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Hi all,

I also had the issue, that my new Mac Mini M1 with a Samsung 32“ display didn‘t power on the display each morning. Both was new bought so I didn‘t know if it‘s Mac or display related. So I cross changed the display with my homeoffice display the last day to see if the issue also occurs with another display on the Mac.

After 4 hours of work on my homeoffice desk, my Samsung display starting to count a counter in it‘s onscreen menu and told me, that there were 4 hours of inactivity and the screen will get powered off after 30 seconds.

I checked the settings menu of the display and there is a setting to auto power off after a defined time and this was enabled by default! So after disabling this, also on my Mac Mini, the display woke up this morning as expected.

So this was NOT an Mac issue. This was simply a stupid setting, done by Samsung...

Regards,
Denis
 
Same problem with Asus XG279Q display. Also pink squares. The computer is fully unusable at its current state. I will be calling apple today and will send it back if a fix is not made.
 
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Cross posting from another thread:

My M1 Mac Mini is 2 weeks old and has been experiencing Sleep Mode crashes. 3 nights/days in a row, I put my computer to sleep, turn off the wireless keyboard power, turn off my version 1 magic mouse and turn my off my monitor. The next morning, when I turn everything back on, I get the message that my computer unexpectedly restarted. I'm using a DELL Monitor connected via HDMI and currently have a Thunderbolt 2 to Thunderbolt 3 dongle attached.

Specs: Mac mini M1, 2020
16 gigs of ram
1TB SSD
MacOS Big Sur 11.1

Also to note, every so often, I'll see the little pink pixel squeares spread-out across the screen as seen here: https://www.macrumors.com/2021/02/21/pink-squares-external-display-m1-mac-mini/

I'll do a test tonight by unplugging the dongle to see if the problem still occurs.
 
Just tried macOS 11.3 Beta in hopes that this problem would be fixed. Nope, still has the same problem. So submitted it as Beta feedback...maybe it'll get some attention that way.
 
I've had similar wakeup problem with LG monitor (27UK850-W) on Mac mini m1 8gb/256gb ssd, Big Sur 11.2.2; was using LG supplied usb-c/c cable, switched to LG-supplied HDMI cable, still no success. I either had to reboot the mini, and/or pull out the HDMI (or USB-C) cable and reinsert, in order to wakeup/talk to monitor. Also using apple keyboard, Magic Trackpad 2, I haven't had any issues with Bt. Fwiw, the mini is resting vertically, in a stand, which I heard makes a difference.
 
I've had similar wakeup problem with LG monitor (27UK850-W) on Mac mini m1 8gb/256gb ssd, Big Sur 11.2.2; was using LG supplied usb-c/c cable, switched to LG-supplied HDMI cable, still no success. I either had to reboot the mini, and/or pull out the HDMI (or USB-C) cable and reinsert, in order to wakeup/talk to monitor. Also using apple keyboard, Magic Trackpad 2, I haven't had any issues with Bt. Fwiw, the mini is resting vertically, in a stand, which I heard makes a difference.
I’m still having the same issues as well. I installed 11.2.3 this morning, no change — I have the LG 32UL950 USB-C to USB-C connection (TB3). System crashes unexpectedly, sleep/wake issues, and scaled resolution automatically resets to default resolution.

I‘ve typed this temporary fix so many times it’s frustrating in many of these posts! Only way I can have a stable environment is changing the DisplayPort setting on the monitor from 1.4 to 1.2, not an optimal choice to utilize the best features of the monitor that I spent more on than the M1.

I have a case open with Apple that I have been updating for over a month now. I purchased the M1 on 12/24 and received it around the second week in January. I contacted support this morning to update my case that 11.2.3 didn’t make any difference. I may have to speak to a senior technician the support rep said if I want to request a refund or exchange at this point

— really frustrated with the whole situation.
 
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Same problem here. Mac mini M1 with Big Sur 11.2.3, plugged with a USB-C -> DisplayPort cable to an ASUS PG279Q (2560x1140 @ 120 Hz).

I have to switch the display's input from DisplayPort to HDMI and back to get a picture, and sometimes have to unplug the USB-C end of the cable from the Mac mini.

It's annoying Apple still hasn't fixed it...

(Fwiw, this is my cable : https://www.amazon.fr/DisplayPort-T...s=uni+usb+c+displayport&qid=1615359897&sr=8-5)
 
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Same problem here. Mac mini M1 with Big Sur 11.2.3, plugged with a USB-C -> DisplayPort cable to an ASUS PG279Q (2560x1140 @ 120 Hz).

I have to switch the display's input from DisplayPort to HDMI and back to get a picture, and sometimes have to unplug the USB-C end of the cable from the Mac mini.

It's annoying Apple still hasn't fixed it...

(Fwiw, this is my cable : https://www.amazon.fr/DisplayPort-T...s=uni+usb+c+displayport&qid=1615359897&sr=8-5)
That is a slick looking cable! I think the real issue is the M1 with USB-C (TB3) connections aren't fully compatible with all these displays that can support these type connections -- it's a Big Sur issue.
 
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