New Mac Studio not working with Acer Monitor. It shows up in Displays but picture is Black

<< Without having the display show up in preferences, I can't lower the refresh rate. >>

Safe Mode does a number of different things. Hold shift at startup, but have your userid and password at the ready.

A parade of unusual things happens.

• Your Mac loads just enough of the kernel to do a disk check. Then it proceeds to do a disk check. This can take an extra about five minutes.

• your userid and password are required, even if you normally auto-login. So have them handy.

• Your Mac adds ONLY a minimal set of Apple-Only extensions, Not including graphics acceleration extensions. Screen updates will therefore be wonky and slow, but it ultimately should be correct.

• Your Mac assumes defaults for as many settings as possible, including screen resolution. This is the key for re-setting the screen, but there is a little more to it: Resolution is likely to be lower and settings ordinary. Use this as a starting point to customize settings to your liking.

Any changes you make in Safe Mode will "stick" in regular mode after you restart.

• after restart in normal mode, your Mac will take slightly longer to start up [once] because it rebuilds some system caches.

"Works in Safe mode, fails in regular mode" implies "It's something you added".

How to use Safe Mode on your Mac

How to use safe mode on your Mac - Apple Support

So, I have a mac mini (2018). Monitor was working fine until 12.2.1. when it updated to 12.3 the exact same problem happened.

Note: over HDMI 2.0 the mac and monitor work fine.

over DisplayPort, if I do the SMC reset (power cable out for 10 seconds) and then restart, the apple logo shows up on the acer for about 10 seconds, and then the acer goes to sleep, and isnt detected at all. Without having the display show up in preferences, I can't lower the refresh rate. I can 'wake' the acer by 'switching inputs' but going back to DP in, it just shows nothing (this is different from showing 'no cable attached'.)

I did try using DP1.1 instead of 1.2. No luck. I tried multiple thunderbolt->displayport cables. No luck. Mine are active.

The monitor seems fine. It works fine with my windows computer. It also works fine with my CalDigit dock with my mac laptop.

But the KVM I use is a DP kvm so HDMI isnt really an option.

I saw other postings on websites with people having similar issues with their mac mini's.

Today, thinking I may as well just update my mac anyways, I picked up the Mac Studio. It has the EXACT SAME ISSUE. I *really* like this monitor, and would like to not replace it. And I'm pretty much convinced this is something in the mac (and something that breaks as soon as it boots up, but pretty early).

Did something change between 12.2 and 12.3 that could affect this? And why is it only breaking my acer ultrawide monitor (and not my samsung 4k monitor, which is also doing DP 1.2)?

Just to add, I now have a mostly working workaround, but it's temperamental.

Connect the HDMI cable so I can use the monitor. It shows up as 75Hz. Lower the frequency to 60 Hz. and then connect the display port cable (it will now detect and show up the monitor as a (2) monitor, and set it to mirror the display of (1).

Edit THAT one to be 60Hz, and unplug the HDMI cord.

Now I have it working, using DisplayPort.

Thing is, when I reboot, it sometimes goes back to 75Hz, and I have to go through this headache again.. I havent figured out the pattern yet of why it decides to do this.

(note: it can't be 'software I installed' because the mac studio was a clean install.. I didnt even use my time machine backup). Not saying safe mode wouldn't have used a lower refresh rate, but this is definitely an issue with the clean OS from Apple / a possibly bad 75Hz implementation on the acer -- although I've driven it up to 75Hz using freesync on the windows machine).

does it light up at a lower resolution?

from the User manual:

ok

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change it to a refresh rate of 60 HZ as opposed to 75