Big Sur 11.1 External Display Issues!

I had a somewhat similar situation, only my external monitor (29" Apple Cinema Display) would reduce the resolution to a much lower one - all on its own. After a lot of trial and error, I found if I unplug the Cinema Display and unplug the adapter (converting Mini-Display to Thunderbolt), wait about ten seconds, then plug in the monitor first, then plug in the adapter, it resets to the higher resolution it was previously set to.

I was thinking it was the adapter, but with everyone else's issues they are having, maybe it is just the OS software. Anyway, this methodology might help some of you. Good luck and take care,

Jim

Yep so I'm here with the same problem. Just bought the M1 air, very very happy with it other than it doesn't like external devices. Did expect this problem - but shouldn't have to. I have an MX master mouse - which has connected without issues. Plus an LG external monitor, which right now is displayed neon pink & lime green. Which is seriously disrupting my work flow & giving me eye strain. So erm.. is this gonna get patched or are we basically waiting for the next OS.

If Apple Support reads this - I'm very happy with my M1 machine, I am not happy about this problem. My mother also uses Big Sur on an M1 macbook pro & she has had to buy a new bluetooth mouse to achieve a connection. These issues seem to be totally device specific to me (as in, its not a universal fix), which would explain why it has been so difficult to patch the issue.

I recently got a 2019 Macbook Pro and my external Cintiq no longer works (displays for about 10 seconds, then flashes on and off every few seconds). I thought it was Big Sur problem because my 2016 Macbook Pro with Catalina works fine.

I tried numerous different USB-C to DVI converters with no change in behavior. Finally, I rolled my 2019 back to Catalina and still have the exact same issue. So it would seems it's not a OS issue but a hardware issue.

This is so frustrating. I got this new laptop to be *more* productive and all I've done is chase this issue.

Well...just bought a new J5Create USB 3.0 to HDMI (JUA354) adapter to connect 2015 iMac to Acer monitor, as my older (last year!) Insignia adapter did not support Big Sur. Couldn't get the new one to work after lots of trying, saw the new 11.5.2 BS (!) update, so just installed it. NOW my Acer monitor is working, but ONLY mirroring! And still doesn't show up in Control Center or Displays so I can't unselect mirroring! Wow, what an improvement. Is this stuff tested before getting put out there, and if so, with what? At least I know the monitor works with Big Sur...but a mirrored-only display is not the least helpful! Apple, what the heck??? I guess they ARE trying... :+O

Well, Part 2. Before I gave up and walked away for the day, I thought I'd restart the iMac one more time, after installing the 11.5.2. Lo and behold, when it came up, my Acer monitor was working as the second display and showing up System/Display Preferences! MAYBE it IS fixed...hoping it will hold and stay this way. If so, thanks Apple, really! Took a long time, but thanks for getting it done - assuming this is for sure a fix! Only took 2 hours out of my day... :+O

Also just updated to 11.5.2. But there is no change that my problems should have been solved.

I am on a 2020 MBP M1 and still running my external HDMI connected 34“ MSI monitor (via Anker USB-C hub) with 30Hz by 3440x1440 and bluetooth mouse stutters. No issues or whatsoever if I connect the USB-C hub to my windows laptop! It runs out of the box with proper 60Hz and no stuttering.

I have a 2010 Mac Pro running Mojave. I was able to boot the hard drive with an external hard drive encasing through my MacBook. Since the MacBook has a built in screen I was able to access the drive and apple finally came out with an update that I performed and now my external displays receive the signal. I wonder how many people ran out and replaced their computers? My 2010 Mac Pro is upgraded and a great machine. I think it's ridiculous that apple literally refers to it as 'vintage' & 'obsolete' & even criminal that they stop allowing it to update. The fact that I can no longer air drop with my Mac Pro says it all.

I downloaded the driver for the J5Create Adapter, and until I updated to 11.5.2 the Adapter status window kept telling me it saw my monitor, but there was some kind of "space" issue with a code I have never seen before. When I did the update, it then told me it saw the monitor and it should work - but it didn't, until I unplugged the adapter again, replugged it all in, then it showed me the mirrored monitor, and only after I did ONE MORE restart did the Displays status show the monitor and the Gather Windows button, and get it to work properly as an extension and NOT mirror. Now it is working as it was before I did the Big Sur update, maybe a little faster, which is probably the new J5Create adapter...

Good luck!

I have a new LG 27UP850. And 3 Macs. The MacBook Pro running Catalina works fine with the external monitor. The MacBook Air running Big Sur 11.5.2 when connected via the same USB-C cable blanks out both screens. The built-in screen flickers on occasionally as if it is trying to locate the signal. The iMac running Big Sur 11.5.2 when connected from ThunderBolt2 to DisplayPort, also blanks out both screens with the same behaviour of turning the built-in screen on occasionally for a second as if it is trying to find a signal.

I have tried reseting the SMC and PRAM with no luck. I have tried changing the external monitor from DP1.4 to DP1.2 with no luck.

It would seems that Big Sur has a persistent bug in regards to external monitors since I have read of it happening since early in the year.

I have a single monitor (LG QHD Display), connected via an Anker Premium USB-C hub and an HDMI cable. My Mac is "MacBook Pro (15-inch, 2017), 2.9 GHz Quad-Core Intel Core i7, 16 GB 2133 MHz LPDDR3" running Big Sur 11.5.2.

With my laptop display open, I get the proper 31.5-inch (2560 × 1440) resolution, all is good. But when I close the laptop (to keep my cat from biting and cracking the display), poof, "About this Mac" still assures me that I have 31.5-inch (2560 × 1440) resolution. But in System Preferences -> Displays, I see Scaled->1080p. When I choose "Default for Display" I sometimes get back full resolution, like today. This will often persist, and I am not bothered again for a bit. Hope it helps.

Just bought a new Dell 2720Q and everything worked fine for a couple of days with MBP13 2020, 11.5.2. But this morning my monitor started running at 30 Hz refresh rate and it cannot be changed. The dropdown list is disabled. Tried to reset SMC - no changes.

Whats going on? How to fix this?

Here's the fix:

Open display settings, hold the option key and click on "Scaled" option at Dell monitor settings window.

Click "show low resolution modes" checkbox.

Close the lid of Macbook.

Choose the optimal resolution for you (mine is 2560x1440) and set the refresh rate to 60Hz.

Open the lid.

If you still have 30Hz refresh rate - after previous steps go to the display settings again, choose the "show low resolution modes" and now Hz-dropdown will be available.

Macbook pro 16" , BigSur 11.6 on Docking Station HP-G5 with 2x HP EliteDisplay Monitors 27" .

The docking station is working great with other non-mac laptops.

On my macbook I only got it to recognize the external monitors once and they worked as one (mirror).

I tried all usb-c ports and the laptop crashed twice.

I would really like to know if this is OS related or if I need another docking station (and if yes which one would it be).

Either way, a huge disappointment for a 4.000$ laptop.

I replied earlier, I was blocked. Then darrenhumphrey suggested a new cable. I then recalled then that I had a similar experience with my Raspberry Pi4. I had been using a cheap adapter and cable on it, and high resolution would not work. I switched to a HDMI-micro to HDMI cable, problem permanently solved.

On my MBP, I was using my older Anker USB/Ether/HDMI adapter and an ancient HDMI cable. Result: kaka. Like the Pi, I found that issue (almost completely) resolved when I got a new cable. I bought a 4K USB-C/HDMI adapter and a 4K cable, and now it works. Sometimes the MBP forgets, but when it does, all resolutions are available in System Preferences::Displays and one click solves it.

To me that's about as good and A::B comparison as it gets. The only difference before/after is the cable, and this supported by a similar experience on a completely different system (Pi, using the same LG monitor). It may be a case of Apple actually being more correct with Big Sur in the age of all these new monitor resolutions. Hope it helps, people.

In case anybody is wondering, this problem has still not been fixed.

I have a 16" Macbook Pro (2019) - I had zero problems before the 11.1 Big Sur update in December 2020. Since then, my Macbook has not been able to use external displays with via Thunderbolt 3 / Displayport.

The problem is not and has never been about HDMI. The problem is with Displayport profiles over TB3.

The anecdotal evidence attributing the problem to cheap cables detracts from the focus of this thread.