After Monterey 12.3 upgrade, can't run 2 usb-c monitors

Good work! Looks to me like the dreaded dual-monitor disease, just a different variant…

I would file the bug report and forget about it because dual-monitor bug reports have been in existence since at least 2018. They all share one common feature, which, sadly, gets in the way of Apple fixing them: none of the monitor manufacturers state full compliance with Macs, nor do they offer drivers, updates, competent tech support etc. No putting money where the mouth is. Quite the reverse, in fact, they all take the money and, err, instantly go to sleep, permanently blanking out.

Still, who knows, the next macOS release might reverse this troubled history. All the best.

Interesting: I've tried to boot my Mini with only the "el cheapo" portable (don't know the brand) and it got stuck. As a "sidekick" to the HDMI connected LG it works.

Definitely there is a bug here. Now we can just hope.

I had everything working perfectly up to this 'upgrade' to 12.3, now the second monitor fails to initialize and I must reset into settings after every reboot... and even if doing that, I still don't get the 4k resolution anymore.

Apple, please resolve this!!

Something that used to work like a charm, now doesn't!

It’s infuriating that apple released 12.3 with this issue when it was identified during the beta period across multiple versions. They knew about it and choose to release it anyway without a warning to Mac mini users. I expected better from Apple. This issue cost me several hours.

Actually it was the same issue, just manifesting itself differently. When I switched one of my 2 usb-c screens to hdmi to troubleshoot the bug, the hdmi connection would not survive a reboot, I had to disconnect the other usb-c screen first and only boot with hdmi, then plug the usb-c screen, or the hdmi screen would never wake up.

I have the opposite issue. I have a 2019 16" MacBook Pro and everything was fine until I upgraded to 12.3.1 last evening. Now dual monitors won't work and LG Monitor Manager says the monitors I have connected are unsupported. They the same 24" LG monitors I have had connected for years. VERY FRUSTRATING!!

You have it, I’m using your link for “Up to two displays.” They don’t mention mandatory HDMI but that’s how I read it for hooking two displays.

FWIW, it's looking like only LGs taking the hit...I assume you're on 12.3, right?

Perhaps.... No I've had updates bork my setup in the past and so I tend to be more cautious.

Understood, thanks.

Thanks for posting the links.

I've responded under Mac mini but had to pick 12.2.1 as the operating system - Apple hasn't even updated the OS dropbox to include 12.3 as an option yet!

It worked fine before yesterday and 12.3! How can that be "LG's booboo"?

Hummm... why not having a unique ID can be a security hole on a consumer grade monitor?

Same as mac-IDs, it depends on how strict one is about security. Remember, not one consumer monitor claims full workability with Apple, backs it up progressive fixes//updates/drivers etc.

It’s an issue for HDCP content which Apple has a huge stake in. To me, plugging the hole is very, very Apple.