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

Which two LG monitors did you buy? I have two 4K LGs connected to mine, and it *mostly* works (it occasionally forgets about one of them on wake from sleep and needs a restart to fix that; this has become better with 11.2, but it isn't by any means completely fixed). I am not using adapters.

I bought my first Mac Mini in 2014 and it worked like a dream. It handled two monitors about as easily as any piece of hardware which would likely play a part in landing a craft on the moon.

Fast forward to the M1, with regard to two monitors, we're back in the 1950s.

What is going on?

[Edited by Moderator]

I agree, I bought this computer almost 4 months ago and ZERO support for dual monitors... That said, if I go back to an Intel model that is basically outdated moving forward. Might still try to return this mini one monitor is a joke!

I don’t buy this for a second. Apple have been running multiple monitors across multiple graphics cards from different manufacturers in mixed bit depths, refresh rates, and resolutions since at least 1987.

What we are seeing here is straightforward bugginess, of a kind usually reserved for Windows setups, where multiple monitor support has been around for a far shorter period, and has had nowhere near macOS’ capabilities. Also we’re not just talking about multiple monitor problems; it’s mainly about connections using anything except the built-in HDMI port; even single monitors are having problems via direct usb-c or via adapters.

A reasonably good analysis, Alastair Houghton. Thank you.

Another issue, in the mix, is that the “USB-C” connectors, on the M1 Macs—the ones with the Thunderbolt symbol—are actually USB4—the newest USB standard.

This new standard has its own “wrinkles”, with regard to various modes.

They are not to be confused with the old USB-C/Thunderbolt-3 ports on the Intel based Macs.

The main thing that will take time to catch-up to this change are the adapters and cables: there are, at least, three levels of cable compatibility, all with their own logos, which are supposed to help consumers know they have the correct products.

However, I have yet to see these logos displayed where they should be, let alone on sites where one may order such—even from Apple.

This is not, truly, the fault of Apple’s M1 based Macs—Apple is simply making this change contemporaneously with the M1 change, in order to be prepared for the future.

Unfortunately, however, the rest of Apple—let alone the rest of the computer industry—has yet to catch-up to this (coming) future.

michaenh wrote:

Apple have great products and I do have several Apple products from pad, phone, laptop and so on.

First time meeting and experience are very important.

I’m sure Apple knows this.

If not, they will relearn it, I expect.

Hi Alastair

Thank you for that, and the time it took you to put together.

All good but however, I don't think expecting two monitors to work (as the main blurb says they will) is much of a reach as far as tech expectation goes. I even bought 2 x new 4k monitors from a well known brand to go along with it so there is nowhere for Apple to hide as far as some bizarre compatibility issue goes.

It also worked fine with the seven year old Intel chip so it's not like we're breaking new ground here.

Even the £70 Apple adaptor didn't do it.

However, you look at it, it's not good enough.

I sent my Mini back after a month as, as a developer, I need at least two screens to be productive. I will probably get a Mac Mini when the next generation comes out and I am sure that it actually works properly (Bluetooth as well as external screens). Objectively, I think that it is so weird how many people on this forum have been willing to make excuses for Apple; it's all the classic lines from an abusive relationship. It is their fault. Every single other device I own has been able to drive my two screens (The Lenovo Chromebook ThinkPad C13 I bought as a stopgap runs a Ryzen 3500 chip which is new with Chrome OS and yet it is still able to drive 3 external monitors). Even the Raspberry Pi 4 is able to do it. I honestly think that the M1 chip is a phenomenal advance and will drive increased advances in the chip world (although I really don't think AMD is getting enough credit for what it is doing). Nevertheless, that is not excuse for Apple's complacency and willingness to take its user base for granted (although, judging from this thread, they know their audience).

But they do work (modulo the remaining wake from sleep issue) if they’re attached the way Apple specifies. That is, one HDMI display and one display over Thunderbolt.

The thing causing the most trouble for people in this thread is trying to use adapters of various sorts, and it’s confusing because naïvely it appears to make sense that they should. Unfortunately, the best intentions of the engineers who designed many of these standards (in terms of the various compatibility modes, some of which are optional) have in this instance backfired somewhat and created expectations of compatibility that don’t match reality. I wanted to explain some of that in the hope that it will help people understanding what will and will not work.

I agree that some of the bugs need to be fixed. But that still won’t help if you’re expecting to use adapters hanging off the USB-C port.

To be clear, I’m not trying to make excuses for Apple. I do, however, think that there are a number of genuine compatibility issues that are clearly causing confusion and need explaining, hence my post.

Alastair thanks for the deep technical explanation and I am guilty of trying a bunch of adapters as well, however it is WELL documented that even people trying to use this machine as Apple intended (HDMI and USB-C) for dual monitors still have trouble getting an HDMI monitor to work well and stay working with a second monitor plugged in to the USB-C port.

I'd much prefer to stay with a future proof machine such as the M1 Mac mini, however Apple has released 2 major OS updates and neither has fixed this issue for almost all of us on this forum making it hard to justify continued use of this machine. I honestly wish I had just gotten the Intel version at this point cause I'd have two monitors and I can easily justify converting the Intel mini into an office server down the road.

For some time I have been surprised by all the problems people have reported getting monitors to work with the M1 Mac Mini. I attributed them to the possibility that people in some countries may have received ‘Monday production’, or some such. Why? Because I experienced no trouble connecting two monitors, and - after a lot of trial and error - now have three monitors working with a 16 GB Mac Mini, in a flight simulator running X-Plane.

Note that my monitors are relatively inexpensive and ‘old’. If it will help anybody, here are the details:

One monitor is actually a Westinghouse TV model LDD2240 (1920 x 1080 @ 60 Hz), and it is connected via HDMI to HDMI.

The second monitor is a Flatron W2252TQ connected via VGA on the monitor to a Belkin VGA/Thunderbolt adapter to a Thunderbolt port on the Mac Mini.

The third monitor is a Dell model 2007 FPS (1600 x 1200 @60 Hz) connected via VGA on the monitor to VGA/DVI-I adapter to Startec.com’s ‘USB 3.0 Dual Head Graphics Adapter’ to USB-C on the Mac Mini. This required a free DisplayLink driver to be downloaded from Startec’s website, and then turned ‘on’ in the Mac Mini.

I have switched the connections between the second and third monitors, since both are VGA, and there was no problem either way.

Do all three monitors light up immediately when the computer is turned ‘on’? No, sometimes there is a very slight delay, but as soon as I activate X-Plane, all three light up.

The first time I used the Startec device, the Mac Mini saw all three monitors, but X-Plane still only saw two. My wife suggested that the program was acting like a spoiled child and did not want another monitor to come into the ‘house’, so I went into System Preferences and designated the 3rd monitor to be the ‘main monitor’. (Who is a big boy now?). That did the trick, and X-Plane saw all three monitors. When I went back through System Preferences and redesignated the monitors to their proper positions, all three were active on X-Plane. It was as though ‘introductions had been made and the proprieties observed’.

Don’t challenge me on the logic of my explanation. Computers are smart and the program uses Artificial Intelligence, so maybe they can no longer be treated like adding machines. As Ann Landers used to say, “If it happens, it must be possible.”

One final point: The Startec device cost $83 and their support was excellent. I would not have known about the driver without it.

Two Monitors working on a Mac Mini M1 16gb

I have a successful set up. I bought the mac mini with 2 - BenQ PD2700U and a OWC Thunderbay 4 (thunderbolt) which also has a DisplayPort 1.2 port at the back.

I have a HDMI connected directly to one of the monitors. The thunder bay is connected to the Mac Mini M1 via the included thunderbolt cable and the second monitor is connected to the DisplayPort 1.2 port in the back of the Thunderbay. I am using no adapters anywhere and all cables are relatively short. Less than 1.5metres.

It works perfectly, wakes from sleep without issue. Have not had to restart I have the set up 4 days already and I work all day on the machine. On another note I do fid some blue tooth glitches, hanging etc. I am running the latest Mac updates as of 20th Feb 2021.

I hope this helps someone.

1 cable is HDMI from the mac mini to monitor one.

Then I have a Mini DisplayPort to DisplayPort Cable connected to my OWC Thunderbay 4. The Thunderbolt 4 from OWC has a DisplayPort Cable socket on the back of it's enclosure. The OWC Thunderbay 4 is connected to the mac mini via a Thunderbolt cable.

I don't know if this may be helpful to anyone, but I just bought and setup my mac mini m1 and I had the same issues with my j5 create Dual HDMI Mini Dock for some reason the displays were mirroring and I could not get it to detect it as separate displays. So I tried my old iHome adapter display and that worked for me. So my setup is the HDMI cord in the back of the mini and I have my iHome USB-C adapter plugged in the back as well with my HDMI plugged in the adapter.

Hope this helps!