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Monterey 12.3 External Monitor/Display Issue - No Longer Outputting Signal

T

turnipfarmer

macrumors member
Original poster
May 10, 2011
31
1
After updating my Mac Mini today to 12.3, my monitor now no longer displays an image via USB-C, just keeps saying on no signal on the monitor.

I have tried HDMI and same issue. The odd occasion it will display a picture but once I shutdown or restart the mac mini it does not display a picture. The mac is booting up. I have had to resort to connecting it to my old TV with HDMI connection.

This is so frustrating

I have tried resetting the SMC which had not appeared to work, also tried downgrading the displayport version from 1.4 to 1.2 (on the odd occasion I did get a picture) but that has not worked either.

Has anyone else having this issue?

The monitor I use is a BenQ SW270C.

This is really doing my head in and was wondering if anyone else has got a fix to this.
 
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Had the same issue with and was using Screens VNC on my iPhone to connect "remotely." My log in screen would appear like normal and after logging in I would just get a black screen. Under About This Mac the display listed was my "Built-in-display". Maybe it was referring to the LED on the front of my MacMini :)

Like you, nothing I did seemed to do fix the issue. I tried a power cycle and that seemed to work... so far.

Mac: 2020 Intel MacMini
Monitor: LG UL500 4K
 
turnipfarmer said:
After updating my Mac Mini today to 12.3, my monitor now no longer displays an image via USB-C, just keeps saying on no signal on the monitor.

I have tried HDMI and same issue. The odd occasion it will display a picture but once I shutdown or restart the mac mini it does not display a picture. The mac is booting up. I have had to resort to connecting it to my old TV with HDMI connection.

This is so frustrating

I have tried resetting the SMC which had not appeared to work, also tried downgrading the displayport version from 1.4 to 1.2 (on the odd occasion I did get a picture) but that has not worked either.

Has anyone else having this issue?

The monitor I use is a BenQ SW270C.

This is really doing my head in and was wondering if anyone else has got a fix to this.
Click to expand...
I just upgraded to 12.3 and had this issue. I was able to get a signal again over USB-C by changing the DisplayPort version on my monitor from 1.2 to 1.1. I then changed it back to 1.2 after logging into MacOS. So far it is stable, even after one sleep attempt.
 
Last edited:
FWIW it seems that the signaling issue was only around the actual upgrade process. I have had several sleep & wakes with no external monitor issues. Running a Samsung LU28R55 on a 2018 Mac mini
 
I have an iMac (Retina 5K, 27-inch, 2020) and I purchased recently a portable monitor Lepow Z1 USB-C and it was working properly with the previous version of macOS. As soon as I upgraded to 12.3, the monitor could not be detected and it shows the "No signal" error. I did all the jobs that were found on the Internet and Apple website like unplugging and plugging again Clearing NVRAM, connecting on the time of turning on, logging in a safe mode, changing the USB-C cable, using the Mac Original Thunderbolt 3 cable and so many other unusual works that somebody said like changing the direction of the cable and so, but no change. I already talked 2 times with Mac support and they still could not fix the problem. The same monitor with the same cable is working with my MacBook which is under the previous macOS version.
It works with some of the USB-C to HDMI adapters but not all. It works with a cheap one which is a no-name random USB-C HDMI adapter but I have another that I purchased more expensive but doesn't work with that.
I just recommend downgrading if you just upgrade it till the moment that a real solution will be there.
Does anyone have a solution?
 
I have big problems here too. I have two Slate RAVEN 27 inch touch displays and they worked perfectly up to Monterey 12.3. Now, however, the two displays are constantly logging off and on again from the USB. But HDMI works! Only the touch function which is controlled via USB is no longer correct. Even if they work, the displays constantly log off and on from the USB and I have to identify them again and again so that the touch function works again.
 
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