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

@emmanuel-0_0 how do you connect your mac to your display? Mac-thunderbolt (usb-c) to Monitor-usb-c? If so, try to connect your Mac-thunderbolt(usb-c) to Monitor-HDMI. You have to get a usb-c to HDMI-cable or a usb-c-To-Hdmi-Adapter. I've read comments here that this worked for some folks. Give it a try.

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.

I think the best thing to do at this time is to call support and open a case. After you do that, you have to keep in touch and contacting them for a solution. The problem is not widespread enough at this point that I doubt it will get addressed at all without anyone who is having an issue calling support.

Hi, I have the same issue as well. I am trying to connect to a Lenovo ThinkVision monitor. I have a MacBook Pro (14-inch, 2021) with the M1 chip. Currently on Monterrey 12.5. I have a HDMI to usbC cable that I know works, because I have used it with an Asus monitor before. However, the Lenovo monitor only has DisplayPort, VGA and another type of port. So first I brought a display port to HDMI adaptor and tried it with my cable, and it didn't detect a signal. Then I tried contacting the HDMI directly and same thing. I have tried following the tutorials to detect displays on the Mac, but when I hold down the option key nothing happens, I can't even SEE the detect display option. Next, I tried lowering the FPS to 49,75Hz, as well as trying all different presets and again, nothing. I have even tried with my dongle, connecting the HDMI through to the dongle and then from there to the Mac, and again nothing is detected. I have tried 4 different cables now, and I know the monitor does not have an issue because it worked perfectly fine with my friend's ThinkPad laptop.

Please fix this ASAP, I have spent the past 3 days buying and returning cables, going through endless tutorials and I am losing my mind.

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

It worked.

Dont know why, but 5k 72Hz is back again.

MB off, Monitor off and unplugged. Used the Apple TB cable to connect them, plugged in monitor.

Starting the monitor which also started the Mac.

All fine. Lets see if it stays stable.

Down again !

Today I plugged in a new Thunderbolt Docking Station while everything was running.

Picture was there (Thunderbolt Link), all good. After a reboot, blank screen on external monitoragain.

The MacOS still has a problem.

Switched to DisplayPort (new Dock has DP) and picture was there gain, 5k

So, your mileage will vary depending on many factors and hardware.

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.

Spoke with Senior level technician Chuck, about this. Two different senior technicians said this is a known problem and the engineers are investigating. Here is how we got my monitor working again.

1) Under energy savings we slide the rule to "Never" and ensured the screen saver was working.

2) Ensured the screen saver was active

3) Checked "System Preferences/Displays" and noticed that only one display was connected to the Thuderbolt Display Port (HUB).

4) Confirmed that only one display was connected by viewing the System Report under "About this Mac"

5) Shut down the MacMini

6) Held the shift key down while starting the Macmini to get into safe mode.

7) Checked System Report and Display preferences and now I see two monitors again

According to Chuck they are looking for a bug around the energy savings features and this is a work-a-round

There is another monitor related problem.

MacBook Air lid closed, external 5k monitor via TB HUB DisplayLink

Sabnzb running, it stops after some time and freezes. OSX freezes when trying to reboot. Forced reboot needed.

Can be reproduced.

But if the MB Air is open, so its display is on everything works, Sabnzb DLs fine, no more freezes.

The MB Air also reboots by itself from time to time, mainly when it sleeps. Switching the external monitor on and off seems to trigger these freezes.

I just updated to Monterey 12.6 and my MacMini still actually detects my second monitor (DVI->USB-C adapter that works fine with Big Sur) but the monitor itself still says "No Signal".

This has been going on across multiple versions and for probably close to a year at this point!

Apple's working on it... right...

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.

That doesn't work. I've tries so many things and nothing helps, it's a problem with Monterey that Apple apparently can't be bothered to fix, as it's been going on for more than a year by now (at least for me)!

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.

Hey everyone, this issue has been plaguing me as well for months, I was on 12.0.1 until like June and decided “I never upgrade what could they possibly break?”

I didn’t see this mentioned, but I found that the “most convenient” fix doesn’t require unplugged and plugging in cables at all. Simply go to the display settings, and change your resolution. For me my 1080p Asus monitor I drop down to 720p, the screen turns on and then just click back to the resolution you want and it should work in that resolution. If you let the display fall asleep though you will need to do this again.