The macOS Monterey 12.3 update was released this month, bringing with it a plethora of complaints. Just last week, many MacBook Pro users complained that they faced multiple errors and restart loops trying to get the latest update, while some ended up with bricked Macs. Now, the latest issue plaguing Mac users pertains to connectivity with external monitors.

Affected users took to Apple Support forums to complain that some external displays connected via USB-C are no longer being detected by Macs after getting the latest macOS 12.3 update. One user noted that the issue persisted even after switching to HDMI connections.

“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.”

Possible Workaround

Some users were able to find a workaround by changing the DisplayPort protocol version to an earlier one, leading to a poorer quality output. It appears that the problem arises due to macOS not recognizing the default DisplayPort protocol version 1.4. One MacRumors forum member explained what worked for them:

“I’ve solved this problem (on 2022-03-15). On my monitor (LG LCD 27 27UN880-B IPS) I’ve went (sic) into settings, and I’ve lowered the DisplayPortVersion from the default v1.4 to v1.2. As soon as I’ve lowered the monitor’s DisplayPortVersion, my Mac with OS X 12.3 has started recognizing the second display correctly. It seems that the new OS X update has issues with a DisplayPortVersion 1.4 protocol (has faster data rate, faster refresh, and stream compression).”

According to reports, it appears that problems with external monitors are cropping up only when third party monitors such as those manufactured by LG, HP and BenQ are involved. The release of the latest macOS 12.3 update has been bumpy so far, with a variety of complaints ranging from issues with game controllers to the bricking of Macs that had their logic boards replaced. So, if you haven’t updated to the latest version, it’s better to wait for Apple to release an update that will fix these bugs.