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Original poster
Apr 12, 2001
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Some macOS Big Sur users who are running the 11.1 and recently released 11.2 update have been experiencing ongoing issues with external displays, based on multiple reports on the MacRumors forum, Apple Support Communities, Twitter, and Reddit.

macbook-pro-touch-bar-m1.jpg

There are at least two separate issues at play, but both are related to external display connections. The problems appear to have started with the macOS Big Sur 11.1 update, and the 11.2 update has not provided a fix and in some cases, has worsened the issue.

The first issue causes USB-C ports to fail to recognize external monitors, rendering external displays unusable and unable to connect. This appears to be affecting both DisplayPort and HDMI displays connected directly and through hubs and adapters.


We saw this issue firsthand after upgrading a MacBook Pro to macOS Big Sur 11.2, with the update preventing an external monitor from connecting with USB-C, and there are several other complaints from affected users. From Reddit:
Upgrading to 11.2 broke my second external monitor connection.
Primary monitor LG Ultrafine 4k (Mac version) connected via Thunderbolt.
Secondary monitor (same model) connected via HDMI->DisplayPort adapter (BENFEI), then DisplayPort->USB-C cable no longer works after updating (worked fine on 11.1 before updating).
macOS appears to recognize the monitor and resolution, as it is shown in display settings, and Apple Support was able to remove into my computer and see both screens. It's almost as if the signal for the monitor to turn on is not being sent.
The second issue results in resolution issues with external displays unable to work at a full 4K 60Hz resolution, instead locked at 30Hz. In some cases, a 4K monitor is only recognized as a 1080p monitor.


It appears that many of those affected with display issues have a 16-inch MacBook Pro, but there are also reports of other Macs with the same connectivity problems. There does not appear to be a reliable, widespread and tested fix or workaround at this time.

Mac users did not experience these problems in the initial release of macOS Big Sur 11.0.1, and it appears that the macOS Big Sur 11.3 update released yesterday also does not address the problem, but there is still some time for Apple to work in a fix before the 11.3 software sees a public release.

Article Link: Some Users Having External Display Connection Issues With macOS Big Sur 11.1 and 11.2
 

smithrh

macrumors 68030
Feb 28, 2009
2,590
1,399
Interesting - my Thunderbolt networking died after going to 11.2 as well...
 

FocusAndEarnIt

macrumors 601
May 29, 2005
4,540
845
No issues on my 16" MBP running 11.2. I use HDMI, ethernet, and several peripherals via one USB-C cable that connects to a hub. Works great.
 

sdf

macrumors 6502a
Jan 29, 2004
509
487
I had problems with external displays on my MacBookPro11,3 in 11.0 and 11.1, but they seem fixed in 11.2. Seem. I bet they reappear after a few days.
 

anshuvorty

macrumors 68020
Sep 1, 2010
2,240
2,486
California, USA
I can confirm that I am having this issue as well. Here is my issue in more detail:
  • I have a 34-inch 3440 x 1440 Ultrawide monitor connected to a Belkin Thunderbolt 3 Express Dock via Displayport to USB-C cable.
  • Whenever I connect the Thunderbolt 3 USB-C (from the dock) to the USB-C cable into my M1 MBA, the monitor doesn't activate.
  • The only solution that I found was to remove the USB-C to USB-C cable from my laptop, open the lid, and connect the cable again. At this point, the monitor is detected in macOS 11.2, and then I can close the lid again.
A little annoying, but I am not too flustered by this issue.
 

cal6n

macrumors 68020
Jul 25, 2004
2,080
246
Gloucester, UK
It’s good to see this on the front page. Let’s get some visibility.

My Benq PD2720U drops to 1920 x 1080 when my MBP M1 wakes from sleep, but still tries to display my higher res desktop.

Turning the monitor off and on restores normality, so it’s an annoyance but it still shouldn’t be happening.
 

sirozha

macrumors 68000
Jan 4, 2008
1,668
2,042
Thats an understatement. Huge issues with external display for me on the M1 MacBook Air. HDMI connection is not recognized after the Mac goes to sleep. I have to unplug the cable and plug it back in and then bang on the space bar repeatedly for the Mac to detect the monitor via the HDMI port on the monitor.

The DP 1.4 (5K) connection on this monitor is not recognized by the M1 MacBook Air at all no matter what I do. It works just fine with the 2020 MacBook Pro (10th generation Intel CPU).

Apple admitted to me (after a month of me badgering them and demanding that the ticket be sent to Engineering again and again) that the M1 Macs have an issue with DP1.4 not being recognized.
 
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ghostface147

macrumors 68040
May 28, 2008
3,655
3,952
I have a Safari slowness issue with 11.2 on a 2018 15" MB Pro with an external monitor. If I open Safari, doesn't matter which monitor I open it on, and open a new tab and drag the tab to the other monitor, it spins for a few seconds and then I can use it. It stays gray with the content of the tab, or gray if it's a blank tab, and after those few seconds it works fine. In 11.1, it was instantaneous. Chrome has no such issue. That's the only issue I see. The external monitor is a Dell 27" Precision monitor.
 
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MDMac

macrumors 6502
Dec 2, 2006
286
38
McAllen, TX
Had washed-out colors and incorrect black levels over USB-C on my LG 27UK850-W since I received my M1 MacBook Air. Issues were resolved in 11.2 final and still are in 11.3 beta 1.

EDIT: I’ve now tested this on my second, identical monitor and the issue is still present.
 
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JPack

macrumors 604
Mar 27, 2017
7,885
13,480
I wonder if this is the reason Apple limited the M1 MacBooks to one external monitor. Having a working external display is a pretty basic function.
 

boss.king

macrumors 601
Apr 8, 2009
4,537
2,727
Is anyone having this other external display issue?

1. I connect my monitor and move some apps over to that display. All is fine.

2. But if any app is fullscreen when I unplug my monitor, that screen/space/whatever is now lost to the void. No combination of swiping or keyboard shortcuts or replugging will bring it back, and I have to quit and reopen the app to be able to use it properly again.
 
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reyesmac

macrumors 6502a
Jul 17, 2002
627
296
Central Texas
3rd party support always lag behind Apples own products. Does that include video and bluetooth drivers? All this gets fixed by the time they release new OS versions. And the early adopters usually have to put up with it. But now that they are selling more macs hopefully more people will complain about these first gen issues and get Apple to correct them faster instead of in major OS revisions. They do work really fast when its something that gets them bad publicity.
 

fumi2014

macrumors 6502
May 21, 2014
326
1,472
California
I've had this issue since I bought my Mac mini M1. USB-C to Display Port (cable straight from the Mac mini to the display - no hubs or anything). At least once a day, it will not wake long enough to detect the display. When this happens, I can VNC in and everything looks fine.

  • It's almost as though the signal to wake isn't being transmitted or detected long enough to really wake the display.
  • When this wake issue happens, on my monitor, NEC PA301W, I also get an error warning me that the display input has not been detected. Even though I keep my Mac running all the time. It's not like I'm even asking the Mac to wake from sleep.
  • But the only way in is by powering off the monitor. When it comes back, sometimes it's all I need to do. Occasionally, the resolution has gone to hell and I have to go in and redo all my open windows.
  • It happens often enough now that I know it's a genuine fault.
  • For the last few years, I had an Intel MacBook Air connected to this display and I never once had the 'Wake' issue.


Honestly, I've been tearing my hair out over this. Hope this thread gets some good visibility and Apple sort it.
 
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star-affinity

macrumors 68000
Nov 14, 2007
1,537
801
An SMC reset doesn't help?

By the way, I think having more than one display connected in macOS is handled pretty badly compared to Windows 10 as far as what I know is possible.

Things I'm missing in macOS that Windows 10 can do:

  • In software, disable one of the connected display as if it was disconnected despite being physically connected and turned on.
  • Have the Dock (Task Bar in Windows) displayed on both (or all) displays at the same time.
  • Have the menu bar being displayed on both (or all) displays at the same time (well in Windows each menu bar follows the application window, but in practice it becomes like having a menu bar on each display if having one app on each display).

Or am I missing some setting in macOS to achieve something like the above?

Edit:
OK, I see the menu bar is on both the MacBook Pro 13" (2018) display and my external display using Big Sur 11.2 here at work. Don't know why the menu bar only show up on on the main display of my old Mac Pro (2010) with Big Sur 11.2 at home. At the same time Big Sur isn't officially supported on that computer, so can't really complain I guess...

Edit 2:
The menu bar missing on my second screen was due to the setting Displays have separate spaces being disabled in Apple meny -> System Preferences -> Mission Control.
 
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Böhme417

macrumors 6502a
Mar 11, 2009
751
940
On 11.1, I had an issue with the display randomly not being recognized. The computer would be awake, but the monitor would still be asleep. Power cycling the monitor and unplugging and replugging didn’t fix it. The only thing that fixed that was a restart.

Now, on 11.2, the display will wake up with a multicolor pixelated mess from sleep sometimes. Luckily, this is remedied by unplugging the cable from the computer and plugging it back in. Still annoying!
 

Earl Urley

macrumors 6502a
Nov 10, 2014
584
281
It seems ridiculous to me that Big Sur 11.0.1 would not have this issue, and then it's broken ever since that version.
 

fluffy

macrumors member
Aug 7, 2003
48
2
I've had an ongoing issue where whenever my M1 mini wakes from sleep, the display scaling will be all wonky, and I have to power-cycle the monitor to fix it. This is apparently a common issue, too, judging by the replies I got on the Apple forum, and unfortunately 11.2 didn't fix it. And this is on the internal HDMI port.

As a workaround I tried connecting my monitor to my Thunderbolt dock, but unfortunately that wasn't passing through HDR capabilities (even though my dock claims to support HDR), and in SDR mode I can't get the color calibration to be even remotely accurate. So for now I'm just getting in the habit of power-cycling my monitor a bunch.
 
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okan

macrumors member
Oct 26, 2015
36
14
There is a bug with DP 1.4..Started with 11.1 now goes on with 11.2..I think they broke something while trying to fix this ->
  • LG UltraFine 5K Display may incorrectly display at 4K resolution on Macs with M1
 
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Clix Pix

macrumors demi-goddess
No issues here with a 15" 2018 MBP connected to an LG 4K Thunderbolt 3 display. The connection is direct between display and computer, using the supplied Thunderbolt 3 cable, with the display's other cable and power adapter plugged into a surge protector, and everything is working as usual.

I also have a 13" M1 MBP but have not connected it to an external display since I haven't needed to do that, as it is more of a secondary machine rather than the primary one I use for editing photographic images and such.

Both machines have been on Big Sur 11.2 for the past couple of days.
 
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