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

Same issue here.

I've tried two different monitors (LG and Arzopa), tried HDMI on both, USB-C on one, different ports on my Macbook, and different cables. Some solutions say to switch off Automatic Graphics Switching but my option for that is gone.

My monitors only work if I plug them in during a fresh boot.

Having this issue as well. Tried multiple adapters... no success. It will connect temporarily to an external display, but after about 5-7 seconds it goes blank. I connect primarily to a Black Magic Atem Mini for work purposes, but also have an LG ultrawide display that this happens with. I have not tried using my OWC Pro Dock yet which will go Thunderbolt 3 to DisplayPort... but for sure all USB-C to HDMI options are not working.

Maybe a workaround, but not for free. Today bought a ANKER PowerExpand+ 7-in-1 USB-C PD Media Hub EUR 31,99 from Amazon.

It works with HDMI cable. Max resolution 3200x1800. Not the best, but it's more comfortable to work.

Nevertheless, I expect Apple to fix this bug immediately. If this takes a long time, the question arises of clarifying this in court.

Unnecessary investment in cables and adapters, massive limitations in daily work.

Continue testing everything I have. Unfortunately do not have a single monitor that supports DP1.4, only DP1.1 and DP1.2. Absolutely useless now. Both Mac pro 2013 and Mac mini 2018 are now paperweight. Now thinking on how I can roll them back to big sur or at least 12.2.1…

Absolutely disappointed! Keeping all the rest of our macs in the office without updates for now.

[Edited by Moderator]

Same here,

Issue resolved with recent update 12.3.1 MacBook Pro 16", 2019 with hp U32 4K HDR monitor.

Resolution up to 3840x2160 is working fine.

But nevertheless, apple made a fool of itself with it. This bug was known or untested. No quality assurance. That's amateurish.

OMG: after update 12.3.1 my vintage monitor dell E228WFP working perfect since I bought the mac mini, is now useless.

I have been an owner of about 15 apple mac book, imac. ,mac mini and iPhones , tablets over the years: its the first time I think about changing everything to windows.

after 12.3.1 it fixed my HP U32 4K - connection DP -> USB-C with old cable continues to work as before.

for some reason dp -> dp between hub and monitor and usb-c -> usb-c between mbp 16 and hub - still doesnt work.

Update done, not good.

Now the black screen witch the LG monitor seems solved, the mac boots and i am able to login.

But … My external disks don’t come online, i see my desktop, can move the mouse but cant start anything, no finder window.

Will call Apple Support again …

Now solved with Apple Support.

Update 12.3.1 did not solve it for me.

No black screen, but frozen screen.

We had to remove 2 specific prefs files, reboot the computer and now ok.

Taken steps:

In your SSD or HD:  system library - preferences - look for com.apple.windowserver.plist - remove it

Also on your user library -  via hidden key press: go to the Finder - click  in top menu on Go - press key option on the keyboard - choose Library - Preferences - ByHost - com.apple.windowserver.plist - remove it

Advice: contact Apple Support if you are not easy with this to execute on your own.

Reboot - it should now be ok

In my case this solved it.

I assume there will be another minor Monterey update because of this

Still not resolved for me. My monitor seems to be recognized by my Macmini again but now HDR options are not consistent across the USB-C ports. After working on the computer and having it sleep when I woke it back up it went to a blank black screen. That required me to unplug and replug it in only to then experience the lack of HDR content.

After updating to 12.3.1 there no signal from my Macbook (Early 2016). My old Dell P2719HC worked fine with 12.3. After the current update theres no signal at all. I've tried everything (disconnecting, power off etc.) but nothing works for me. Please fix this, Apple!

My Mac mini ist connected to a TV via HDMI. After upgrading from 12.3 to 12.3.1 my computer does not recognise the TV correctly, i.e. I have a picture but the color profile simply says "Monitor" and I am no longer able to switch the sound output to the TV set. Seems that the HDMI handshake is broken somehow. Very annoying.

I just installed 12.3.1. on my Mac Mini 2020. The changelog only mentions the Mac Mini 2018 and my second monitor that's connected via a DVI -> USB-C adapter still says "No Signal" after a restart, even though Monterey still lists it in the "Display" settings and I can still move the mouse cursor to it. My main HDMI->HDMI monitor is still working fine. Ffs Apple, get your s...tuff together!

My portable monitor on MacBook Pro connected via USB-c is still not working properly. It fades light to dark and blacks out at random times. I have an open ticket still but no solution and no responses to my follow up emails.

I had a very helpful & competent APPLE 🍎 supporter doing this together with me with a lot of patienece, the screen came back after the process described by you. I said I don’t believe it 😵And see, it went to sleep after about 2‘. He asked me if I would prefer to work wit a supervisor or wait for an update…. I chose the later and hope it gets solved with 12.3.2🙏🏻 However he tried everything. In 🍎 I trust. Thanks for the time invested 🙏🏻