Mac Mini (M1) dual display doesn't work.

My apologies, I am simple user. No idea what is an automatic. I will try to research on it ....thank you for your suggestion.

M1 Mac mini. One monitor usbc to hdmi or display port. Second Hdmi to hdmi . Both fire up. Works like a champ !

Thank you!

I've known Apple for too long. This problem will be fixed soon. :-D

I have the same issue on my M1 Mac Mini too. I'm connecting using an HDMI cable for one screen and USB-C to HDMI cable on the other. Both screens work perfectly fine until I log back in after a reboot, sleep or shutdown.

As soon as I log back in, both screens flicker. Sometimes the screens have swapped positions too, with the background image changing on one screen and the refresh rate changed from 144Hz to 60Hz. The menu bar is still visible and I can get to System Preferences so that I can 'reset' the screens by changing their properties back to how I had them setup originally.

If I use only one screen, there doesn't seem to be an issue either with the HDMI cable or USB-C to HDMI cable.

Just a shot in the dark here, but several have reported that Big Sur 11.0 broke HDMI support on the 2018 Mac mini (previous setup worked under Catalina). One user said that upgrading to Big Sur 11.1.0 beta fixed the problem. Not the M1 Macs but possibly all this is a Big Sur issue.

Not advocating that you update to a beta version since there is a risk of not being able to downgrade back. Just something to ponder.

People might find the information in this link helpful (talks about cables and specs):

https://blog.startech.com/post/tech-talk-display-technologies/

Might offer some help in deciding what adapter or cable to try for your specific monitor needs.

Thank you. Sorry to hear that swapping the cables between monitors didn't work for you. The other thing I've noticed is that in System Preferences - Displays - Arrangement - my monitor on the right now remains the 'dominant' one. Before I swapped the cables, the arrangement of the two monitors switched around every time I rebooted the Mac mini. Is it also something to do with how that arrangement is set up? I'm not technical enough to know, but it seems to be another factor. Maybe check that the monitor connected to the USB-C port is the 'dominant one in the arrangement and that you've dragged the white bar to the top of the dominant monitor (as mine is) and then reboot the machine? Hope that helps.

I had the same issues, flashing display, pink squares, working until sleep then issues were back. My solution currently driving 4 monitors from my m1 Mac mini: monitor 1 - usb-c to hdmi, additional monitors - using Apple usb-c to USB 3 adapter to a Dell D3100 displaylink that can drive (3) 4K monitors, 2 HDMI and 1 DisplayPort. Also requires installation of the displaylink MacOS driver https://www.displaylink.com/downloads/macos Everything works flawlessly as expected on reboots. Any use of the m1 Mac mini hdmi port results in issues, so not using it at all. Using MacOS 11.0.1

Hi there,

as many of you, I am also experiencing the same flickering issue with my Mac mini M1 (8GB unified memory, 512GB SSD).

I am using two identical ViewSonic VX3276-QHD (2k) Displays at native 1440p resolution.

I am in search for a solution since 3 days now. I tried some of the things proposed here as well (e.g. swapping the HDMI cables after booting just with the USB-C cable plugged in as described by chgough54 on page 3).

Let me share with you what else I have tried, so you might save some time and money in trying to find a solution.

All of the following didn't solve the problem for me:

• Updating to macOS Big Sur 11.0.1
• Updating all installed Apps to the latest version
• Disabling all Login Items
• using HDMI -> Displayport cable
• using HDMI -> HDMI cable
• using USB-C -> Displayport cable
• using USB-C -> Displayport cable
• Booting in safe mode
• Booting in diagnostics mode
  • diagnostics test always get’s interrupted with an error message after checking the network connections (no matter if ethernet is connected or not) that tells me to start it again by using diagnostics boot
• Using the guest user account
• Creating a new user account
• SMC reset
• NVRAM reset
  • holding ⌥+⌘+P+R on boot for at least 20 seconds didn’t do anything noticeably for me, not sure if it worked or not, couldn’t perceive anything, tried it several times
• Reinstall macOS Big Sur

I had a chat session with the Apple support yesterday for almost 1,5 hours with the result that they recommended me to reinstall macOS Big Sur. I tried it today, but had no luck as you can see in the list above.

Following that, I called the Apple support and reported, that the reinstallation didn’t help and that I’m out of ideas. The only other thing that they could come up with was to completely erase / format my hard drive and perform a clean and new  installation of macOS Big Sur.

I am actually a bit reluctant to do this and gladly I came across this support thread here which gave me some relief as I now see, that I am not alone with this problem. That also made me think that probably a complete erase of my hard drive won’t fix that issue either, as it might be a Big Sur software or hardware issue when so many people experience the same thing.

But let’s keep hoping and searching for a possible solution.

Maybe Apple finds this thread and looks into these issues soon.

Lars

I've had difficulty getting dual monitors to work but I think there is a way to get around it. Neither of my monitors are 4k. As soon as I logged into my mini after power up the desktop interface began flashing black, the dock was unreachable and I had to shut down.

Prior to trying to boot sucessfully, my dual displays are set up so left monitor corresponds to the dominant screen (parent) in the arrangement section of display preferences. My left screen is straight HDMI to HDMI. My right monitor is USB-C to HDMI and is set up to be furthest right edge arrangement in display preferences.

When you boot, wait until you know your computer will be requesting your password to login. Turn your right screen on first. Wait for it to display an empty screen with only your wallpaper given it is the child screen - it won't prompt you for a password. Then turn on the left screen, and after a few seconds 'the arrangement' will switch causing the right of the screen to be the parent. You will be asked to login on the right sided monitor.

This happens to work for me.

Hi, pmiles. The problem I see with your explanation is that several people tried to connect the second monitor to adapters for different types of monitors (USB C to HDMI, USB C to DP) and they had the same problems. So it is not just with two HDMI connections but with others too (except VGA). I'm going to wait until someone posts some results with the DisplayLink and buy that one. I don't want to waste money on adapters, cables or hubs without being sure they really solve the issues.

My DisplayLink showed up today, and it did NOT fix the issue. I have one monitor direct to the Mini via a Thunderbolt cable and the second via HDMI using the DisplayLink. Didn't change a thing. It was a bit worse. From a reboot or wake up, the HDMI monitor would not work at all, and I had to jump thru hoops even to be able to use the one Thunderbolt monitor as just switching the mode no longer resolved it as it did before the DisplayLink.

hi all ,I think for sure is not adapter think the problem, I have two dell monitors one connected with HDMI> HDMI and the second monitor USB-C > USB-C ,the DELL have USB-C input ,

after sleep or reboot or new start of Mac mini M1 the only way to light up the second monitor (usb-c ) is switch off monitor and switch on again ,

so don't spend money to change adapters ....