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

I have the same adapter. No flickering, but that monitor connected to the VGA occasionally forgets what resolution it's capable of. After sleep it will sometimes drop into 1024x768 and refuse to go any higher. Unplug and replug will reset it and everything is fine again, even for a few sleep/wake cycles. That problem is very intermittent, but persists with the VGA adapter.

Not having the pink artifacts issue but had major issues with trying to get certain adaptors to work correctly. Still hoping that 11.1 fixes the fact that my mac mini just loses its brain and forgets the screen alignment every time the screens go to sleep.

I had the same issue after updating to Mac OS Big Sur version 11.1 RC the problem has been solved and it's working without any flickering. It remembers the right Screen resolution for each screen which it was reseting before. Now it has been 2 days I am working on 2 4K Monitors and it works without any flickering

BigSur 11.1 only solves the flickering issue.

In this update, the resolution on my 2nd monitor is still out of sync and the top horizontal menu bar moved out of the display that I could not select the menu. I switched the cable back to the HDMI->DVI cable and things went back to normal and the resolution on both monitors are correct at 1920x1080.

AH man. The update NOT fix my problem. Bummer. It did change it a little bit tho. Throughout today, I've had the mini forget the resolution of my monitor and refuse to any higher than 1024x768, screen was just black and unrecognized after sleep, and random pink blocks.

Same as before: simple unplug and re-plug fixes the problem.

Now I call apple. BUMMER!

Just to be perfectly clear here... this really is a first generation M1 Mac computer. It is expected to have issues. It is also really a first generation OS for said device (Big Sur), so it too, is expected to have issues.

Not trying to say Apple shouldn't have tested the devices more before actually releasing either, just pointing out that when you are buying a first generation anything, you are basically buying a device with many unknowns attached to it. It's not the same as buying one of their INTEL Mac computers which have over a decade of iterations under the belt.

Many of the try this and try that adapter merry go round has been more an effort on the user's part to try and get a device to work as expected on an INTEL Mac... come to find out, many of the issues had to be fixed in Big Sur by Apple. So it was never the cable or the adapter for many... it was the OS. It may still turn out to be a limitation with how the hardware was implemented for others. Whether that means Apple is going to fix it in the next iteration of M1 type Macs or do some sort of return, we don't know yet.

The reality is, everything that went wrong with those who adopted the M1 Macs early, is a wealth of information and knowledge for Apple to use for improving the device. The devices will only get better. It's a painful road for the early adopters, but a year or two, these things are going to be much better than they are today because of early adopters.

You're all pioneers. And as pioneers, you get to be the first to own one and help with the molding of it's future with every little thing you learn about it along the way. Apple can't possibly test every possible piece of hardware that can be attached to it, nor can it test how people will use it... that's where you all come in. We all come in. We are the world's largest test group in the world... it's like we make up the super-computer of testing... we have the ability to find things that Apple didn't in less time than it would have taken them to find them.

Apple certainly didn't attempt to connect 6 displays to an M1 Mac... but some intrepid M1 pioneer did. Just saying you are all pioneers at this point. The safety net is in the INTEL Mac lineup because over a decade of pioneering has made them pretty **** stable/predictable... and it is that history that has a loyal Mac base behind it. The M1s are going t get there... just not right out of the gate.

Ape Menu>System Preferences>Displays>Arrangement Tab

The blue rectangle (screen) with the white bar on top is the Primary Screen. You can drag the white bar to the blue rectangle you want to make primary.

For me, if resolutions of monitors are not remembered/retained upon wake then the assigned primary monitor is not remembered either. For now two 4K monitors running at 1080 resolutions allows Mac to remember all settings after wake. Not ideal but better than before.

Wiping my drive clean entirely (deleting the partitions and creating a new one) and reinstalling the OS is what solved this issue for me. It was running fine on 11.0.1 after I did that.

Unfortunately I had other graphics issues (pink , white and gray artifacts) so i returned it today.

Since this is my work computer I don’t have time to deal with it, but will follow the threads and see when these issues resolve, and I’ll re-purchase them. The machine, without the issues, is otherwise amazing.

Talked to the apple tech this morning... they had me do this: (It still didn't work tho).

Apple Support:

1. Unplug all cables on displays for 1 min

2. Factory reset displays to default settings.

3. Deleted the following files (from BOTH /Library AND ~/Library:

a. /Library/Preferences/com.apple.windowserver.displays.plistBehost/

b. /Library/Preferences/ByHost/com.apple.windowserver.displays.XXXX.plist

4. DO not use “auto” select on the monitor. Set it to the actual display connection type.

5. Update firmware on monitors

I'm stuck right now on updating the firmware on my monitors. I don't know how to do that, so I'm researching that right now, then I need to leave apple a voicemail and I'll continue with the tech from there. Still working on it. Still not working.

Going a little crazy here. Have done firmware updates on both monitors, waiting for next apple 2nd tier call on Monday. Meanwhile, I re-read the M1 Mini Spec sheet...

That very first line under Video Support says "simultaneously supports up to two displays"... it seems to imply one display MUST be a Thunderbolt Display and the other MUST be an HDMI (my emphasis).

Under "Thunderbolt 3 digital video output supports," it mentions adapter support BUT NOT simultaneous dual displays. Notice that?

Under "HDMI 2.0 display video output" it says support for ONE display. Does that mean, if you use the HDMI, you can only have one monitor plugged in?

I know reading comprehension is a thing, so I'm trying my best here, but maybe the thing is if we want dual monitor support we MUST be using one HDMI and one thunderbolt monitor? In other words, anytime you plug something into the HDMI port, the other monitor BETTER be a thunderbolt monitor, or it just won't work. So, even two thunderbolt monitors won't work, because you'll need a HDMI to thunderbolt adapter, which would then cause it to not work under the 3rd rule?

SOOOOO.. Is anyone running dual monitors using thunderbolt and HDMI, sticking to the first rule and getting it to work correctly?

Just an FYI, agreed/confirmed there are all sorts of M1 Mac Mini issues with dual-display (16 pages on this thread alone!) It should "just work" but it doesn't, for whatever reason - but there's enough of a hub-bub that Apple seems to know about it and is working on it... I happen to have two (2) identical Lenovo Q27 screens (QHD native resolution, HDMI and DP) and have refresh/flickering/reset issues after sleep as well.

The 11.1 update helped things greatly, but I can report that we've taken a step back with the 11.2 beta for whatever reason. There are work-arounds that I have figured out (turn on one display, log in if Bluetooth isn't affected from wake - sometimes it is and the Magic Keyboard doesn't work properly - then turn on the other display). Bottom line = I need to remember to physically power off both displays before leaving and going to sleep, and then turn them on one by one after the Mini is awake... akin to unplugging and plugging back the connection cable. Having both displays on power-save (amber light) and then waking the M1 Mac Mini, thus waking both monitors at the exact same time = highly problematic and unpredictable. After trying every cable and adapter known to man, I am 99.9% confident it's not a cabling issue and simply some bug or problem with the way the M1 Mac handles dual displays as my HDMI and DP are both "native".

My current solution still requires going into Display control panel to re-arrange each time when each monitor turns back on and reverts to native resolution and common refresh (60 Hz), but I can live with that right now... ah, the price of early adoption, but it's worth it in my opinion!

No, that isn't what it says. It specifically says "one display… connected via Thunderbolt and one display… connected via HDMI 2.0".

And indeed, connecting two displays like that does work, but there seem to be a few teething difficulties.

That is an interesting point, in that it seems the display is most likely using DisplayPort Alternate Mode rather than Thunderbolt, although from what I understand, all Thunderbolt ports also support DisplayPort Alternate Mode (in addition to Thunderbolt Alternate Mode).

Additionally, it actually works. It's just that after wake from sleep, it sometimes forgets about the HDMI attached monitor (the USB-C one is fine), and very, very occasionally it blanks the display for a second (which might just mean I need a better cable, though it is the one that came with the display, which should be good enough).

Furthermore, Alastair Houghton and @All:

The M1 Macs are using a further standard: USB4.

USB4 is the first USB standard that mandates the USB-C connector.

The USB4 standard includes DisplayPort and Thunderbolt-3.

However, there are still USB-C cables that only support subsets of the USB4 standard.

(Note: the USB4 standard stipulates labels for cables to specify whether they support the entire USB4 standard, or certain subsets thereof. Unfortunately, it may take some time for cable manufacturers to come into compliance, especially from the “cheep” sources.)