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

I do agree lukethesky. What I mentioned about delete the Mac and install the MacOS is regarding the crashes I was facing. It is clear for me that there is big problem on Mac Big Sur regarding displays management, it is everywhere... What I did help me to at least work with two monitors, it is not a reliable solution, I am not turning it off or putting to sleep. Every time I turn my monitors I have some issues on the arrangement but it is manageable. Apple needs to fix it, I gave up, I found a way to live with the bug until they provide the correct fix.

Yep, that's right. That's what I got as well. I think I posted a screenshot on the last page or maybe before that.

Just out of curiosity, in that "About This Mac" screen click on the version number 11.0.1, and it'll show the build number (I think that's what it's called).

Mine after I re-installed the OS is 20B50... I didn't check it before. What is yours?

Sadly I don't think it was even fixed in 11.1, I think it was fixed in 11.0.1 build 20B50, at least it was fixed for me.

In any case, I am returning mine because it still has another issue which may be hardware, unresolved by these recent updates. :(

Good luck you guys. :)

I followed all 16 pages of this thread in the hope that it would help me connect a 3rd monitor to my new 16 GB M1 Mac Mini, and was surprised to see that so many had trouble getting two monitors to work. I have not had any problem using two monitors. I guess that I am lucky, as I am certainly not an expert in computers. FWIW, here is my set up:

The left side monitor is a Dell model 2007 FPb monitor (1600 x 1200 @ 60 HS) connected via Thunderbolt on the Mac Mini to DVI on the monitor.

The front/main monitor is actually a Westinghouse TV model LD2240 (1920 x 1080 @ 60 Hz) connected via the Mac Mini’s HDMI to HDMI on the TV.

Because the computer is being set up exclusively as a Flight Simulator, I would like to be able to look out on both sides and through the front windscreen. I do not need gaming quality graphics, so the current monitors do the job, and I am getting frame rates in the mid 30’s. Before any gamers gag at that FPS, it is in the sweet zone for X-Plane. What it will be with 3 monitors remain to be seen.

It's been a little over 24 hours and I just saw one tiny glitch. I saw TV snow on my secondary monitor for a second, then it fixed itself before I could do anything. Seems like the problem has 99.9% gone away with the new adapter. Very weird.

Thing is, I already ordered the replacement mini. I've currently got the 500SSD and the replacement will have the 1TB SSD. So, I'm still replacing this one, albeit on my dime.

Anyways, things are looking good.

Good luck!

I have the Mac mini M1 (500gb storage and 8gb ram) with BigSur 11.1 and still only one monitor works. I have two 24" Apple Cinema displays, one has always worked with a USB-C to mini-Display port adapter. With an HDMI to MiniDisplay port adapter the HDMI output only works on restart for me, and then the display from USB-C no longer works. When I unplug the HDMI port fed monitor the USB-C fed monitor takes over but then the HDMI won't come back on. Preferences knows there are two displays and lets me flip the orientation, but neither display will ever come on at the same time.

yes the two displays work fine (when they work), but the HDMI screen settings disappear to lesser and greater degrees depending upon if your using separate spaces. the name of the monitor disappears and an app that uses that name then reports monitor not connected.

moffcom wrote:

It has a DVI connection that changes to a USB C via an adapter= USB C (thunderbolt 3) to DVI female that connects to the long DVI cable.

I don't believe that will work. At least at present, my understanding is that the M1 Mini doesn't support HDMI over USB-C, which is almost certainly what that adapter is relying on. You may be able to find a different adapter that uses DisplayPort or Thunderbolt over USB-C and that can provide a DVI output; or you might be able to find a USB-C to DisplayPort adapter and then a DisplayPort to DVI adapter (I'd go for a powered one, as that's much more likely to work… the passive ones probably rely on support for some kind of fallback mode, which might well not be present in an adapter).

Just updated to 11.2 and it does NOT fix my dual monitor issues. I have two Apple cinema 24" displays. Either one works fine when plugged into a USB-C to mini-display port adapter. I've tried three different HDMI to mini-display port adapters and none of them work even with the update. In preferences under monitors you can see there are two displays, and it clearly knows it is a LED Cinema Display but will not display on both at once.

Ironically, the 10m (32 foot) HDMI cable I have connected to a projector works perfectly and has no wake-from-sleep issues. The manufacturer-supplied 1.5m (5 foot) cable for my monitor connected via an adapter however, doesn't help. Just seems that macOS doesn't understand display adaptors any more.

Hi--imo there are two problems for your Mac Mini M1. 1) yes the HDMI doesn't work. I have a Mac Mini 2018 and the HDMI doesn't work with Big Sur; but 2) even though I think your T3 ports have separate controllers your M1 only supports 1 display off the Thunderbolt ports ("One display with up to 6K resolution at 60Hz connected via Thunderbolt and one display with up to 4K resolution at 60Hz connected via HDMI 2.0") So only 1 display if the HDMI drops out. My Mac Mini 2018 has 4 Thunderbolt ports, 2 to a controller, so I can display two monitors--I do have dual display support (though I'm supposed to have 3 including the HDMI). I would think the Mac Mini 2021 Intel (with 4 Thunderbolt ports) also can display two displays even if the HDMI goes with Big Sur. The Mac Mini 2021 Silicon M1 with today's Big Sur...not good!

MacSupernova wrote:

I'm afraid I have to revise that. The flickering is back again. I have now tested on the DVI to HDMI. That works, but then only with 30 Hz. Apple needs to fix the firmware. Thanks Apple!

…

Then you’ll need to provide Feedback directly to Apple, such as through Product Feedback - Apple.

No amount of posting here will change any of that (except to the point that people’s suggestions, here, can help).

How long are the cables?

Thunderbolt to hdmi?