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

Update: My monitor is still not working right. I am using a 4k Samsung LU28R55 monitor hooked up through USB-C to display port Moshi cable. After upgrading to 12.3.1 I thought the disconnection was solved but it hasn't been. The monitor doesn't come back on if the computer has been sleeping for more than 20-30 minutes. I have spent a total of at least 5 hours working with two apple support reps. The first rep said he would be taking the lead on my case and I spent 2.5 hours working with him. We tried to grab computer logs but that failed. I sent in information and setup a follow-up appointment with him only to be ghosted. I followed-up and then spent 2.5 hours working with the second rep trying to capture logs and upload the information. I had to repeat all of the information the first rep asked me. Capturing the logs failed again.

My monitor is still not being recognized well by my mac mini 2018 intel and the HDR content randomly can be selected by unplugging and replugging. My HDMI port has similar issues and when I can get that to work the colors bleed slightly. I have also notice an issue where I will have an apple headset plugged into the back of the computer and it will stop recognizing it. Between three genius bar visits, text messages, and two support calls with Apple I have spent over 14 hours trying to get this computer working which is ridiculous. If my genius bar visit this weekend or 12.3.2 doesn't fix this I am going to demand a replacement from Apple.

I'm having the same problem... MBP 16 w/ AMD Radeon Pro 5500M 8 GB and my display is a Dell u4919dw.

9 times out of 10 when I plug the display into my MBP nothing happens (the monitor stays black and/or displays no signal from device). The other 1 out of 10 times it will sense my MBP but the resolution can only reach 3840 x 1080 rather than the full 5120 x 1440. Have wasted hours trying to debug and have tried everything including deleting the .plist files but nothing has worked! Really hoping 12.3.2 fixes it...

This has happened to me as well, Mac mini 2018 updated last week to Monterey 12.3.1. 2 HP Pavilion 27q displays. One connected via HDMI and the other connected thunderbolt. Both monitors worked for over a week and they worked fine this morning. But this afternoon when logging onto the computer only one monitor worked. I have unplugged both monitors for 3 minutes with the same situation. Both monitors worked great for a couple years and now after an upgrade one quits working.

Apple we need a fix.

My exact setup (HDMI + USB-C), except that I'm using the Mac Mini 2020.

The problem was (supposedly) fixed in 12.3.1 for the Mac Mini 2018, at least that's what the change log says, so it's weird that it still appeared for you too.

My new mini mac 2/22' setup w LG 49" HDR w C cable worked great, forgot to turn auto update off, next date, did not work, only under a hdmi cable, so not able to have my 5180x1440, did the update, worked great for one day3, then had to mess with, come back to the c once, now no longer works on C...

Perhaps to direct statements or questions to directly to Apple

through their 'Product Feedback' Portal may be more efficient?

• Product Feedback - Apple

//www.apple.com/feedback/

Hardware & Software 'product feedback' can follow tedious

paths; from main entry points, within the above website.

Certainly beats other attention getting schemes one may envision.

Thank you so much for posting this! I just called Apple and the rep tried to "problem solve" with me but I explained that we had lost so many hours with IT already trying to solve this and that there are pages and pages on this website that so very clearly show that no tech has been able to fix it yet. So.... he reluctantly skipped those problem solving steps and is just sending me the adaptor! I had already spent $30 on an HDMI cord that someone else had suggested (worked for a day but then the cord - where it meets the monitor - would get so hot, that we would have to unplug it and let it cool and then replug it in for it to work - scary). So, YAY! And thanks so much for the suggestion!!

Yeah, they sent me the exact same one. Cord works fine with my older laptop running Catalina. Several of the techs I have spoken with have not even heard of this problem. The final I received last night was that we need to just wait for the next update.

I have the same issue as others.

Running 12.3.1

Displayport via a USB-C connection on a CalDigit docking station.

Monitor HP E273q

Works fine on HDMI. Is not recognised on display port.

Cables all checked,

everything power cycled multiple times.

Monitor factory reset (is on DP 14.)

SMC and NVRAM reset

New CalDigit dock tried.

Apple case opened .

This didn't work for me. I have both an M1 Macbook Pro on 12.4 and an Intel 16in Macbook Pro on 12.3.1 and neither laptop detects my LG 35WN75C-B monitor. I sent it back to LG and they said there was nothing wrong with the monitor too.

The problem seems to be related to DisplayPort connections. I can attach to the display with a USB-C to HDMI connector adaptor but that means another cable attached to the laptop. I want to run it off my dock which only has DisplayPort as an option. Apple need to fix this.

MacBook Air M1, it just DL the 12.5 update and my external LG 5k went dark.

All tips from the net did not help, no video via Thunderbolt.

Connecting via HDMI works and also brought back power supply via TB cable from the monitor.

But no 5k output, or only 5k via shareware SwitchRes only in 30Hz.

Right now its 3440x1440 in 72Hz.

LG WP4095X-W Monitor

My HDMI port on my 2018 Mac mini stopped sending a signal, yet I can get a signal from my Hagibis USB-C Hub Display Port. This happened after formatting and reinstalling 12.1. An upgrade to 12.5 solved it for about two weeks and the problem returned. The update to 12.5.1 did not fix it.

I just made the mistake to update my MacMini from 10.15 to 12.6 - now my EIZO CS2740 also says 'No signal' and goes to power save after a while when using USB-C :(

I can connect it via a USB-C to Display Port connector, but that is no fun.

I'm still having this issue with iMac 2020 running Monterey 12.6 with an Apple Thunderbolt Display plugged into an Apple Thunderbolt 2-to-Thunderbolt 3 (USB-C) port adapter, which connects directly to the iMac Thunderbolt 3 (USB-C). The only thing that works to restore the blank display is to keep unplugging that connection and reconnecting. Often, I will lose the display after Sleep, but not consistently.