Monterey 12.3.1 External Monitor/Display Issue - No Longer Outputting Signal

Forgot to mention my monitor: It's a Acer V193 (19" 5:4 with 1280x1024), connected via a DVI->USB-C adapter by KabelDirekt that was working fine on the old Mac Mini (can't remember the macOS version but pretty sure it wasn't 12).

Has anyone else got the problem with a DVI monitor/cable?

Same with Mac Mini Intel and monitor LG 34WK95U  UltraWide 5K.

No problem with monitor Iiyama PL2773HD 27inch.

When I boot in safe mode there is no problem with the LG monitor.

When I add another standard user account: no problem with the LG monitor.

So it seems my standard user account which i used during the Monterey update is somehow damaged because of that Monterey update.

Tried to remove the caches etc. to see if it would help but no luck.

So I have some workarounds but not that nice.

I had contacted Apple Support.

We assumed there is something damaged in the used account during the upgrade proces but no fix yet available.

The whole thing seems to be random. I contacted Apple support (do that too, everyone!) and shared my screen with them and they actually saw the second screen, while I didn't. When I then set the second monitor to mirror my main one, the image was there all of a sudden (tried that before, didn't work). After a restart the image on the second monitor was gone again and mirror mode didn't bring it back. The support guy had me try a couple of things (safe modus, create a second admin user, unplug the cable,...) but nothing worked. The Mac went to sleep and when I just woke it back up, the image was back again all of a sudden (even on the login screen) - I bet a restart'll bring back the "No Signal" message though (edit: yes, "No Signal" again).

I just wanted to add, I am using a 13" MacBook Pro, 2019. I use a usb-c to usb-c portable monitor 15.6 by Lepow. It has worked perfectly since 2020 until the 12.3 update. I have done countless restarts, unplug, plug in, reset NVRAM PRAM also multiple times, I tried HDMI on a USB hub I have and finally I tried setting up a new account since that seems to have worked for some people. Last week, after multiple calls to support, they had me plug in and unplug the monitor and then record the logs and send them in. I received this reply: "...I just got a response back from engineering and they said that the logs came out perfectly (whew!). They also confirmed that this is apparently a bug (so we were both right in that respect). He added that they are supposed to be coming out with an update soon that will fix the problem, which is a relief. I can’t necessarily say WHEN the update will be out, but the language the engineer was using led me to believe it should be soon...."

I am really struggling without the use of a second display. I even ordered a new one out of the box JUST IN CASE it would work. It did not so I returned it. My portable display works fine on my mid 2012 MacBook Pro running Catalina 10.15.7 but I cannot use that as a main computer for work.

If anyone has any other suggestions on what I can try to do to get my display working I would appreciate it.

This thread was helpful. Changing from DP 1.4 to DP 1.2 worked. But before this upgrade the second monitor would go to sleep and not wake up, so I have been setting the computer to let the monitors go to sleep. I do not know if the fix resolved the sleep issue.

Mac mini (2018)

3.2 GHz 6-Core Intel Core i7

64 GB 2667 MHz DDR4

LG UltraFine (27")

LG HDR 4K (32")

Hi,

I tried a lot of things.

Then, I saw this suggestion on MacRumors : USB problem just inverse polarity of connector.

I have an old Dell plugged in HDMI into a USB-C Digital AV Multiport Adapter from Apple.

I disconnected the adapter, inverse the direction USB-C in the Mac and plugged it back in my iMac 2017 5K.

The monitor was instantly recognize and is working fine so far.

I am having the exact same issue: Acer Predator XB253QGP with a Mac mini 2018. Tried with all combination of cables, HDMI, USB-C -> HDMI and USB-C -> DisplayPort. That's totally frustrating.

Please Apple fix this ASAP!

I also have the same monitor issue with my new Macbook Pro 2021. I have an old Apple monitor that worked perfectly for years with a MacBook Pro 2011 and then with my MacBook Air 2019.

I have spend 3 weeks back and forward to Apple support and yesterday dragged monitor and two computers to the Cambridge Applestore. The engineer agreed there was a problem but had no solution.

I have an old Dell monitor at an office in London that the Marbook Pro 2021 works with when plugged into the HDMI - so I am now going to have to go there to work.

I am VERY VERY unhappy with Apple and the fact that they are neither owning up to the problem or giving a date for resolution.

Philip

I am having this exact same issue. The only difference is that i actually didn't upgrade to Monterey, i upgraded the security for catalina 10.15.7. I'm still on that software and it did the exact same thing. The computer and monitor were working perfectly.

Same thing here!

I just bought a MAC STUDIO M1 MAX and when I tried to use my Samsung Odyssey G9 with USB-C -> DisplayPort cable, I got no image at all!

I tried to switch the monitor from 1.4 to 1.2 and 1.1 displayport versions and it still not recognizing the monitor. I bought 2 other different cables and the problem persists!

The only way to use the monitor is using HDMI, with this HORRIBLE resolution!

My old mac is with bug sur was working pretty fine with this monitor!

So the conclusion is that Monterey can't use displayports at all!

I'm wondering how a multi-billion company releases an OS with that limitation! What a shame!

I'll probably going to return my MAC STUDIO and, if one day they fix that s*, maybe I buy it back again.

I think I may have figured it out. After a lot of trial and error, switching monitor signals and everything I could try (I spent over 2 hours trying to come up with a resolution)

I would try the following

-Plug the display port from the mac into another computer and switch it to another display port setting. (I went to 1.1)

-changed cords to make sure it didn't work with the other cord.

-I reset the computer 3 times and turned the monitor off and unplugged it.

-Once I did that I turned the computer on a 4th time and I plugged it in and it started to work again.

Hopefully this helps. It seems like I just had to cycle through it.

I could get my external display working only after I have enabled sidecar to my iPad (using Add Display option in Display settings). But sad thing is that external display gets disconnected as soon as I disconnect iPad as display.

I didn't expect Apple to build such a messy update. Shame on Apple...

I amusing MacBook Pro 2018 intel with an HP U32 4k external display. It was running just fine for almost a month since I got the external display. I was using thunderbolt port and USB-C 3.2 cable. The display stopped working right after the update to Monterey 12.3. I spent few hours with the Apple tech support and they failed to fix the issue after reinstalling the OS. Apple tech support referred me to contact HP for driver update which was clearly not the case of the external display failure.

I then rolled back to the previous version of the MacOS. Luckily the MacBook was able to detect the external display and working just fine like before.

I hope Apple will be able to release an update for this issue.

Not only mac mini...

my MBP 15" is also impacted, secondary monitor is not anymore detected - I can still manually force connect but the 4K resolution is not anymore available anyway, making it useless for it's purpose :(

Extremely annoying issue, bothering to perform basic daily work...

what was working perfectly up to 12.2, now doesn't!

This is sad, the code quality is decreasing since approx two Years. Almost every release is buggy.

Apparently Apple is more interested on correct gender speech and diversity than on bug fixing and QA/testing new releases.