Big Sur 11.1 External Display Issues!

I have exactly the same issue after the latest update, I have a DELL U3417W and BenQ SW271 attached. The BenQ was not recognised correctly anymore,

After an extensive troubleshooting call with Apple support which didn't solve the case, I had to downgrade to Catalina to solve the problem :-(

Hope they'll fix it soon, I really liked Big Sur (before v11.1)

(MacBook Pro 16" 2019)

Same issue. Macbook Pro 16-inch, 2019

4k monitor, BenQ SW271, USB-C connection, stopped working after the Big Sur 11.1 update.

*Interestingly, the other Macbook Pro here is working properly with a Dell 4k external monitor, same USB-C connection.

I thought it was a problem with my monitor, the USB-C cable, then I thought it was the port.

1. I checked all connections
2. I detached all cables, cut the power to everything, restarted, everything.
3. Used a new USB-C cable
4. Started Safe Mode and changed display settings to defaults
5. Did the PRAM reset.

PRAM reset worked for a day until the computer was in sleep mode, woke it up, then back to the same issue. Although, when it did work, the way I managed to switch the resolution to 4k was very delicately, as I clicked on one of the other options the external monitor went blank and I carefully moved the mouse over to the next selection carefully and I got visual again. I managed to use the monitor for about a day.

Avoiding a fresh install until I know for sure I need to do this. I don't want to waste any more time and it appears that is not a solution by the OP.

PLEASE CALL APPLE SUPPORT !

It’s very important to make them aware of how many people are experiencing this problem. They are aware of it but we should report all of the display brands and model not working.

Honestly, Apple new OS releases are full of bug. This is unacceptable.

Having the same issue too. Using the BENQ PD2720u. It's hit or miss. Sometimes it will recognize the native resolution but sometimes the highest it'll go is 1600 x 900. When it is acting up, I'll try fixing it with EasyRes or SwitchResX. With EasyRes, it will not display resolutions higher than 1600x900. With SwitchResX, I'll try forcing the monitor to switch to higher resolutions, like 2560x1440, but the graphics become very blurry and pixelated. Seems like this is an issue regardless of the monitor, but anyone specifically have this the BENQ PD2720U? If you do, any solutions?

I've also tried a new thunderbolt 3 cable and still the same issues. I've read that using the WARRKY Thunderbolt 3 to DisplayPort Cable fixes the issue, but I don't believe this method will charge you laptop if your monitor has charging capabilities.

Glad to know it seems to be a Big Sur issue (just really buggy OS overall). I was afraid that it's a monitor issue and would hate to go through the hassle of returning it.

Update: today I plugged a usb-c to DP cable. After a couple of connections I was able to set the display at 4K @60hz. I then disconnected the cable and used the thunderbolt3 cable an I’ve been able to do that again. Honestly don’t know why it worked. However, if I try to connect my XP PEN graphic display too, everything goes back to the original 30Hz condition.

So here's what happened to me. 3 days ago I connected a third monitor (2 monitors connected via usb c new one connected via HDMI) on Mac Mini i7. The next day I restarted and lost my HDMI monitor. Today Duke Energy showed up to upgrade my power meter they turned off the power to my house for 30 seconds turned it back on, all 3 monitors came back.

Maybe a reboot won't work but a full shut down, wait and then start up will help?

I have been having similar issues with Big Sur 11.1

Upon boot my external monitor is recognized correctly and works fine. The problem arises after waking from sleep. My iMac (2020) does not see my external monitor and the only thing I can do is reboot the iMac, after which all is well until the next sleep. Apple tech support claimed it was because the display was connected to a Thunderbolt 3 dock (via mini display port) and not directly to the iMac. I tried everything other people tried (reset PRAM, reset SMC, etc.) to no avail.

What worked for me was to temporarily revert to Catalina. It ran for 4 days with no problems. When I rebooted into Big Sur the problem came back immediately.

Furthermore, under Big Sur I have been having problems with my wireless keyboard. It occasionally goes to sleep for a few seconds, not responding to keys. Then it wakes up and shows me all the keys I have been typing. No problems under Catalina.

Apple: I don't think Big Sur was ready for release!!!

@hellamasta I had the issue about 3 weeks ago, so I'm now 3 weeks on Catalina again and have no issues.

Probably important: I am on a MacBook Pro 16" i7 and did a complete fresh installation of Catalina. Thanks to the container format APFS I was able to move my files without a full TimeMachine recovery from the old partition. So I startet with a completely clean installation.

Sadly Catalina behaves as sluggish as before on the MacBook Pro 16. But that issue existed before when I bought the MacBook and seems to be in the systems nature.

Here you go:

OS X Daily: How to Downgrade macOS Big Sur to Catalina or Mojave

How to Downgrade macOS Big Sur to Catalina or Mojave

Posted: 08 Jan 2021 09:33 AM PST

Did you update to macOS Big Sur but now wish you hadn’t? Are you no longer interested in using macOS Big Sur on your Mac? Perhaps you installed it to try out all new features and changes, but you’re not happy with it due to app incompatibility, performance issues, or some other problem that you ... Read More

This morning I noted in an earlier post that two of the three worked normally. All were shut down overnight. I just noticed on the third one that the "prevent computer from sleeping automatically when display is off" checkbox was not checked.

In 11.01 We were having daily crashes with Kernal panic on M1 Air and M1 Mac Mini

https://discussions.apple.com/thread/252098649

All three have that box now checked, rebooted and now working again. I don't know if it is the fix, if if works for you please post and hopefully Apple will keep working on it.

2020 MacBook 16" (Intel) - Connected to (2) External 4k LG Monitors

Big Sur 11.0 - All worked w/no issues to report

Big Sur 11.1 & 11.2 - No longer able to connect DisplayPort through USB-C to external monitors

This is a major issue that has been going on for over a month. The focus has been all about the M1. I would like to return my MacBook.

The fact you have lost HDR means you still have the problem unfortunately. I have tried different ports and adapters and when you switch to a new adapter, it will generally work for a few days. Then at random when I wake from sleep, it will think the monitor is only capable of 1080p @30hz or something silly.

I then go through the process of turning everything off, unplugging everything and then turning back on, plugging the monitors back in.

Suggest you look at SwitchResX to a adjust the resolution. I've also heard of problems with the Apple Magic Mouse - so I do not use that anymore. I wake the monitor with a Logitech mouse and have no problems. I don't even use the Apple keyboard anymore. I use the Satechi keyboard and it is better than the Apple one that is triple the price. Also try changing the cable to the Monitor. Some are better than others - only suggestions that worked for me on a 34 inch UW screen. The max resolution I could get that looked half decent is 3440x 1440 at 60Hz.

Good luck!

Not sure what you’re talking about here.. I had this issue for months before I changed from USB-C - DP to USB-C to HDMI and it fixed the issue for me?

I agree that the fix obviously has to come from apple, but using alternative dongles / connectors has fixed the issue for me, and a few others too. It’s not guaranteed to work for every setup, but to say it won’t work just isn’t true

I had the same problems as everyone else with my Lg 32 4K Ud99 external display: incorrect resolution, refresh rate limited to 30 Hz instead of 60 Hz, poor image quality. My screen was plugged in with a usb-c cable. 

The real solution has to come from Apple. 

So we still have to continue to put pressure on Apple by calling customer service and reporting the problem here: https://www.apple.com/feedback/macos.html