External Display USB-c Monitor issue

I have been trying to use an Anker PowerExpand 12-in-1 Power Delivery Media Dock with HDMI. I have found that when I connect the dock after each Power up of my M1 MacBook that I have to power cycle the dock before the HDMI signal begins working again. I've replaced the dock with the same model and still having the same problem. I dont have this problem with a small USB C to HDMI adapter from Anker as well though so I'm not sure if its the computer or the dock just doesn't support the M1s. I can't seem to get an answer or figure out how I can troubleshoot more.

I have 3 Macbook Air M1 (base model), all connected to its external LCD monitor. So, basically 1 MBA connects to 1 LCD through 1 USB-C hub. They all have similar issues. On the other hand, my old MBA (2013 mid) does not have any of the following 3 issues.

The 1st issue is similar to yours, slow start for the external LCD after wake up. This happens every single time.

The 2nd issue is, from time to time, the external LCD turns to all black for less than a second, while the MBA's display still on. This happens like once or twice a day.

The 3rd issue is most server, around once in a few days. It goes beyond annoying. Both the external LCD and MBA's owned display turn to pink flash then crash and reboot. Sometimes it doesn't have anything, directly jump into reboot. The problem is, it is unpredictable. It can happen anytime without any symptom.

Hi all,

I have this issue on a MacBook Pro 16, AMD Pro 5300M. It appeared after upgrading to Big Sur 11.1. It didnt not appear under the initial Big Sur update.

I am using a BenQ SW271 4k as an external display over USB-C. When I plug in the display it only shows as a 1080p screen.

looking at the About this Mac -> displays it is shown as a 30,5 inch 1920x1080 display

I find this highly disturbing that Apple would release such an update as I feel my configuration should be a pretty normal one for a creative professional. An industry which Apple should very much be catering to.

I had a brief workaround by restarting the laptop in Safe mode and then back to Normal mode. The screen was recognised as the 4K screen that it is, BUT unplugging it and plugging it back in resulted again in a 1080p screen which is atrocious.

I thought Apple does test its updates, but this unfortunately proves me quite wrong. At the moment my monitor configuration is plain garbage and I am very much prevented from doing my job. Of course being a decision maker in our company on creative platforms, this does ring a very distracting note..

I hope this is actually looked over by someone in Apple with a basic understanding of technology and the matter is resolved today.

thank you

Switching to usb-c to display port cable resolves the issue. But then you would have to use a separate USB cable for the monitor hub. Hopefully Apple will do some due diligence soonish and fix their broken update. Welcome to the Windows world where the users report the bugs.

I have two 31" monitors running Big Sur. One connected using my HDMI port and then I have a USB to HDMI cable running the other. I'm told by Apple Big Sur will not run a dual monitor setup. You seem like you know what you are doing. Any suggestions for a work around?

Hi Sfilimonov,

thanks for your suggestion. It doesnt work as the display is not recognised properly. Its recognised as a 60hz 1080p 30" display, while it is a 4k 60hz 27" display..

IMHO, the new Bug Sur 11.1 caused some problems with the communication with the external display(s). As I can see from above, it is a widely popular issue, too.

chadfromiowa, if Bug Sur does not support dual external displays, it should go directly in the trashcan :) It should support dual external displays, but currently, evidently there are bugs in their official release. Hence the new name. Obviously Apple are all over themselves with the positive reaction to M1 and they are rushing to add new features for these issuing half-baked updates, but seem to be forgetting that none of their flagship models are not currently on M1 yet. Neither is any useful software.

Hopefully they will issue a patch soon. I mean the bug is so blatant that it shouldnt be hard to spot and fix.

In the meantime the only workarounds that I found are

1. restart in safe mode (press shift during Apple logo while booting), then restart back to normal. It seems that it 'resets' some stuff and you are able to scale the display back to whatever its full res is.
2. switch the input of the display. So if the bug appears on usb-c to usb-c input, switch to usb-c to display port, hopefully you have more than one graphics cable at your disposal. Alternatively, if you are running on usb-c to display port and the bug appears there, switch back to a cable usb-c to usb-c. The problem with this approach is if the display is calibrated on usbc to usbc :(

hopefully this helps someone..

best,

Nick

I see many people suggesting the use of additional hardware or third-party software. Don't be fooled into buying hardware or using possibly malicious software. You don't need it.

Additional hardware will not change the results. All available cables, dongles, docks, and hubs use what's called DisplayPort / HDMI Alt Mode, which is a standard that allows for video signals to be passed through a USB-C / Thunderbolt 3 connection. All that the available cables, dongles, docks, and hubs can do is change the connector type to offer you DisplayPort or HDMI connectivity. This will not fix your problem, because display detection in macOS is the problem. Additional hardware can not and will not magically help macOS fix this problem.

Third-party software will not change the results. Third-party software can only reveal the display modes that macOS hides from the user (for generally good reasons, actually). However, the issue here is that macOS does not correctly detect the display and for that reason does not know which display modes are available. Third-party software can not and will not magically help macOS fix this problem.

Display detection is broken in macOS 11.1 and onwards. The problem is in macOS and can only be fixed by the Apple engineers that make macOS. It is literally impossible for additional hardware or third-party software to fix this problem.

To clarify how I did the second install:

1. I had 11.0 installed. I did not want to upgrade to 11.2.1 to avoid any issues.
2. I turned my MBA M1 off and pressed the power button for a few seconds.
3. There I created another APFS part on my SSD (I am not sure how it's named in English version of macOS) with the Disk Utility.
4. I installed a fresh macOS (on M1 Macs the newest version is always installed) of 11.2.1.
5. I booted my Mac from the new part of the SSD and checked if the issue was still there. It was not present.
6. So I upgraded my main system from 11.0 to 11.2.1 and deleted the test one. Now I have one, the old system, and I did not go through the pain of setting up again as new.

Same here. Impossible to choose a custom refresh rate for the second monitor since i have upgraded to big sur. Macbook pro 16" here too but this is obviously os related. This is really frustrating

> "contact the manufacturer of the monitor to ensure it's compatible". Not very helpful...

That answer is a shame.

Big Sur 11.0.1

I’m still having the same external display issues even after updating to 11.1 yesterday. This is pretty unacceptable. Starting to regret my purchase of a MacBook Pro M1.