After updating to 11.1 external 4K Monitor is no longer working over 1080p

[skiabox]

11.3 not working, not all connected monitors wake up, when lid is closed and i try to wake up my MBP16 from sleep. All I have to do is raise the MBP lid, and all screens shine again ..

And all of this on original Apple adapters USB-C HDMI <-> HDMI

😂😆

My 2 monitors are BenQ EW3270U and the connection is with usb-c to usb-c cables that are coming with these monitors.
Please don't use your MBP16 in clamshell mode.
It is not good for its health.

 

[syngress]

Please don't use your MBP16 in clamshell mode.
It is not good for its health.

 

[aaalsubaie]

I have two BenQ EW3270U monitors connected via USBC-USBC and after the 11.3 update they finally work perfectly
I hope nothing change in the future!

 

[studyro]

I'm now using a type-c to dp cable instead of HDMI, and it works perfectly.

 

[fmsaviotti]

Hi All, I have a MBP 13 - 2019 - 4 Thunderbolt - Intel i7 Quad core - and I am connecting my LG 5K Ultrafine through USB-C Thunderbolt. I am on 11.3 and I have had this issue for quite some time, and when the monitor is plugged some app sort of crash (loading without doing anything) and everything gets stuck, and as soon as I unplug the monitor, the app opens. If i then re-plug the monitor it seems working. I had to change also the USB-C Port because it seems to be working better with some port than other... This is total madness... Resolution is working fine but I think there is something wrong on how apple reads external displays in general.

 

[hwojtek]

An interesting issue with an AMD R9 280X with 2x MiniDP and 1x HDMI running multiple 4K screens in Big Sur 11.5.2 (yes, I could not find a better thread).

I run two Samsung UR59C 4K monitors and additionally a Toshiba 4K TV off this computer just to make sure the GPU dies a dignified death before I switch to some modern AMD GPU in the near future. It is a Powercolor R9 280X with latest Powercolor BIOS (I run it switched to stock, although I do have this same BIOS with UEFI for native boot screens, not really useful as Big Sur is only available through OpenCore anyway).

My initial setup was monitors only via DP ports (#1, #2, the default DP mode is v1.2 as set through the OSD menu). On startup, they gave me a strange kind of mirroring on login screen: DP #2 displayed the login screen in 2560x1440 and DP #1 showed the same content, but brutally downscaled to 1280x720 with only the width expanded to full screen, black bars above and below the content. Once logged in, they switch to expanded desktops and I was able to set #2 to 2560x1440, however in 30 Hz only. #1 stays in 1280x720.

Reboot and I connected the TV via HDMI and - lo an behold - while there is still mirroring and DP #1 stays at 1280x720, suddenly DP #2 and HDMI go 2560x1440@60 Hz. I log in and push all screens to 4K, which resulted in the TV (HDMI) in 4K30, DP #2 in 4K60 and DP#1 still at 1280x720 no matter how I played with the display settings prefpane.

Reboot and back to login screen, now the DP#1 is fugly 1280*720 with black bars, DB#2 is 4K60, HDMI is 4K30, all screens are mirrored. I compared the OSD settings of both monitors and started to change them one by one. Surprise, once the DP#1 was downgraded to DisplayPort ver 1.1, it displayed a nice 2560x1440@60 Hz and the other displays mirrored no more.

And then I switched DP#1 back to DisplayPort ver 1.2 and... 4K60 on both MiniDP-connected curved displays and 4K30 on the TV.

So now my procedure on every startup is to wait for login screen, click the left (my DP#1) monitor to downgrade to DisplayPort ver 1.1, click again to switch to DisplayPort ver 1.2 and I have my triple-4K setup running.

That's in MacOS.

The point is, I do not need to do anything like this in Windows I run from the other SSD on the same computer, using the same GPU with the same BIOS. The three screens go double 4K60 + 4K30 just by themselves. I want it in MacOS.

So there must be something that can be done to save me from contortions of the rear-placed, joystick-driven OSD menu. I am open for suggestions, already been through SwitchResX but while powerful, it can not and does not do anything to cycle the DisplayPort versions on startup.

 

[razhangwei]

I have 2 BenQ PD3220U. This helped me to solve the issue. I didn't have to follow the exact same steps - but clicking back and forth between scaled and default display somehow made the OS realize that the external display can be driven to 4K@60Hz.

Thanks!!

My plan is to use Amphetamine app to never make Mac go to sleep (and never disconnect it from monitors) until 11.2 is released.

Osho

Can't believe this actually solves my issue as well! Thanks for sharing, Osho!