Big Sur 11.1 External Display Issues!

I wanted to connect my 2019 27inch iMac with my M1 macbook pro using thunderbolt so that I can use iMac as a monitor but found out that It is not possible due to Big Sur OS(confirmed over apple support call).

Now that 11.3 is out, I am waiting for my thunderbolt cable to arrive and will test it again. I'll post here, might help if anyone has same issue as mine.

I have Big Sur 11.3 but I can't stream videos to my 4K LG OLED TV unless I use the Apple TV application and bought the movies from Apple. GREAT TECHNOLOGY APPLE!!! WHY DO WE STAY WITH YOU???? NOW WHAT??? PLUG AND PRAY LIKE OLD WINDOWS???????

The LG will play H264 and H265 so it's not my TV!!!!!!!!

I can connect to my TV by HDMI cable and get full 4K resolution after I OPTION + SCALED in monitor preferences. This works.

I can connect via HDMI to an ACER monitor that is 19xx by 12xx.

I WILL NOT BUY ANY 4K MONITOR, EVEN FROM THE APPLE STORE, UNTIL THIS GETS FIXED!!!!

THIS IS A **** GOOD REASON TO BUY THE SURFACE PRO!!!!!!!!!!!

Maybe because it’s a 2012 Mac running Windows. Lucky are you that you can even run windows on that pos. Besides, Apple is responsible for providing proper drivers for their hardware in Bootcamp, another Apple problem 🤷‍♀️

Hey! I am very late to this party.

• Bought 16inch MBP April last year along with Letscom USB-C hub
• Fought a little to get my 32 inch Samsung curved monitor (C32F391) to play nicely initially but eventually managed and all was fine
• Today (randomly) Mac thinks the Samsung screen is showing but is blank - I can't shift this.
• Chat with Apple tell me to upgrade to 11.3.1, zap PRAM, SMC, etc - all with no success
• And now I am here with a phone number for further support which I fear isn't going to achieve anything...

I reviewed some answers on this thread but are there still some users who simply can't use their monitors at this time? I would rather not roll back OS if at all possible.

And +1 for beyond shocking QA from Apple...

Apple Cinema HD 23" (Was working fine on Catalina)

MacBook Pro 16" (2019), MacBookPro16,1

DVI-I to USB-C adapter

After fresh install of Big Sur (11.3.1 20E241) the Cinema HD Display works briefly, then proceeds to turn on/off/on/off....

I use a BenQ SW271. There is a button for the brightness on the screen but I just can't change the brightness. Was never an issue before Big Sur...

There is an update for Color Palette but I use i1Studio. That's because Color Palette doesn't work for the Xrite colormunki I use for calibration.

But I don't think this will be the problem?

Maybe it's the cable I use... Not an original Mac cable, could this be it?

FYI, if your monitor speaks the right protocol, there's an app called MonitorControl that you can use that can control the brightness and volume of the non-apple supported monitors. It works great for my Acer ultrawide monitor. It allows brightness and volume control via the keyboard keys.

I downloaded this to a Mac Mini 2018 running 11.3.1 and although I could get it to hook up in Settings > Security > Accessibility to be seen by the Mac when I double click or open it nothing happens. It may or may not work for other users on their Macs w/Big Surs. YMMV--but my on-panel / remotes are Ok for me.

Oh dear! I'm back to square one with my 32" 4k BenQ.

Connected using USB-C to my MB Pro 2019. It seemed to be okay for about a week but since taking my laptop the first face to face meeting in over a year I came back to my home office to find the same problem. The max resolution is 1080p. Awful.

Running the latest update to see if anything changes. Will then reset PRAM, and then SMC to see if anything works.

Forcing me to edit 4K promo vids in 1080p on a monitor capable of much more is unacceptable Apple! Please bring out a fox ASAP.

After the 11.3.1 update, a new behaviour occurred. The secondary monitor works now after restarts, but not if the system boots up. The news are, now, the main monitor is not working after a reboot. This happens sometimes, not constantly. If I reconnect the monitor and change its inputs back and forth, the monitor works again. The Computer is a Mac Pro 7.1 and the monitors are both made by Eizo.

Just updated 1o 11.3 and I'm getting the off/on behavior some other people are describing with my Wacom Cintiq 20WSX. It's very old, I know, but it works fine on Mojave.

Anytime I unplug/plug, it stays on for about 5 seconds but then goes back into the off/on. Same behavior if I edit its display settings in anyway.

I have an LG 32 ud99 updated everything still can not get my 4K resolution since updating to Big Sur you would think with a company as big as Apple they would have fixed this by now about to toss this out of the window disappointed come on you can release all these new products for money but can’t support the avid fan base that has already invested ridiculous maybe time for windows!

Same same. Also intermittent recognition of monitor sound output = infuriating when listening to music or having a zoom conversation when suddenly monitor goes mute. Also, screen still going black... randomly. I've seen these anomalies on other posts so we're not the only sufferers. No suggestions except for Apple techs; PLEASE address these very frustrating bugs & issue an update ASAP!

Updated to the latest 11.4. My external display still does not work. After disconnecting/connecting my monitor displays video signal for about 5-10 sec. and then goes black and then I receive "no signal input" message.

iMac 27" 5K late 2020, thunderbolt 3 (USB-C USB-C), external display NEC EA271U.

Upgraded to Big Sur few months ago with no issues. Recently I have installed the minor update macOS 11.4.1 and after that my 4K Type-C monitor (LG UN880) is showing “no signal” error with no picture although the keyboard and mouse which are daisy-chained through monitor still working. Please help!