Big Sur 11.1 External Display Issues!

This issue has only impacted me since 11.6. It was fine on 11.5.

5K iMac 27" connected via USB-C to a 49" LG 5120 x 1440 display.

After 11.6 update the LG monitor only supports 1920 x 1080 in the middle of the screen.

Spoke with Apple support and tried:

SMC reset - no change

PRAM reset - no change

Deleting 2 plist files in the Library - no change

Altering the monitor USB-C version from 1.4 to 1.1 has solved the issue

I hope that helps anyone else with this problem.

Having a similar, though not as disastrous result. The symptom is my external monitor cycles through a series of full-screen monochromatic displays of various colors when the MacBook is closed and the system goes into screen-saver mode. I've checked System Settings and nothing has changed. This has occurred with the upgrade to 11.6, on an M1 2020 MacBook Proc and a LePow monitor.

Sorry to dredge this back up, did you ever get this set up working. Just got the same dock (Targus Dock180EUZ) and am having same issue.

dock is recognised in system settings>USB and charges my M1 MacBook, but my screen isn’t recognised at all. (Connected via hdmi - hdmi to DVI adaptor…..)

should also add the monitor works when plugged directly in the MacBook with the same cables.

I am having the same issue too. I've a Mac mini i7 with 64 GB RAM . I've connected 3 monitors. 1 is Acer while the other two are 27bw Pavillion HP. They used to work perfectly all together but after the update, only two connect at the same time. If I remove one, 3rd one will start working.

It's just that all of a sudden, 3rd monitor support is gone. I've also tried complete wipe out and multiple reset. One of the monitor is connected directly through USB to HDMI while other two are connected through official Apple Adapter. I've tried mixing them up but basically 3rd monitor only works if either of the first two monitors are shut down

I've had a similar issue. I have the MacBook Air M1 and I've had problems with external displays since the start. I had an old BenQ 27" monitor that used HDMI. I connected the Mac using a Usb-C to HDMI dongle and sometimes the computer didn't recognize the display. When it did, the screen would have this green glitch over the image, or the resolution would be messed up. I thought it might've been the display or HDMI not working properly with Mac so, I sold it and bought Samsung's M7 (that has usb-c). I have no problems with resolution but the computer still has issues recognizing the display. Often I connect the display to the computer and it doesn't recognize it. Sometimes it does, but intermittently. If I log out and try to log in again, the display disconnects.

Logging out, restarting the computer or the display sometimes does the trick but it's never a straightforward process.

I just switched from PC and everything has been great but this. I don't know I guess I was expecting a bit more of Apple's "it just works".

I really don't think it's a hardware issue in my case. I have two Apple Thunderbolt 2 displays. Everything worked perfectly fine on Catalina. Once I installed Big Sur, the problem began. I got tired of not being able to use my two Thunderbolt 2 displays so I reloaded Catalina and again have no problems. My configuration is a MacBook Pro 16" 5600M with two Thunderbolt 2 Displays (daisy chained). I have no plans on upgrading to Big Sur or Monterey until this gets fixed.

This is not just a Big Sur problem. I'm running Catalina 10.15.7. I have an external monitor that I like to switch back and forth between my Windows PC and my Mac. The Windows box has no problem with the cable being yanked out and then plugged back in - it detects whether the monitor is there or not and adjusts accordingly. The Mac gets confused and ***** its pants. How Mac ever got the reputation for "it just works" I do not understand.

By the way, I wrote "The Mac ... gets confused and poops it's pants". Except instead of poop I used another word that begins with "sh" and ends with "its". The forum software here apparently thinks that word is going to offend people, so it changed it to a bunch or asterisks.

My issue (external monitor cycling through test colors instead of going to screen-saver configuration when laptop times out into sleep mode) has been fixed. But that’s only one of the issues reported in this thread.

Same issues here. Philips 49" is not recognized properly and I can't get the resolution wide enough. Had no issues before the upgrade to Big Slur. The monitor is connected with USB-C directly.

Yep me too, have started another thread here https://discussions.apple.com/thread/252186760

Good to know re-installing won't fix it, saves a lot of wasted time!

To those who have asked about how to report this to Apple, I used the following link:

https://www.apple.com/feedback/macbookpro.html

The more reports they get the better!

Here's the link to find a number to call in. I started with online chat and they moved me to phone so skip that online chat.

https://support.apple.com/en-us/HT201232

Hold times were pretty minimal.

To report this huge bug to Apple: https://www.apple.com/feedback/

Please write to Apple. This problem must be taken seriously.

Specifically, since the issue is with Big Sur: https://www.apple.com/feedback/macos.html