MacOS Big Sur 11.2.2 Update: External monitor is no longer detected via USB-C port

I spent some time with apple support on Friday night.

They suggested that I try a usb-c to HDMI cable. I bought one, and this allows me to use my monitor again. I had to do a restart to get it to work.

I hope that the next release 11.2.3 fixes the ability to use my usb-c to displayport cable.

I had the same problem after my macOS was upgraded from 11.2.1 to 11.2.3 today. The external Display was working fine before.

Here is my setup, a MacBook Pro 2019 <<--- USB-C ------ DisplayPort--->> a Dell 4K monitor.

Reset PRAM and Reset SMC didn't work for me.

Interestingly, it worked when I tried it with another Dell HD monitor using the same cable. So I was focusing how to better configure the monitor to be compatible with this version of macOS. (Seems to me macOS 11.2.3 has some issue with its DisplayPort support)

Here is how I solved it by following some document on Dell's website. Hope you can find similar docs on how to change DisplayPort version of your monitor.

"If your system only supports DP version 1.1, monitor may get No Video condition. With older video drivers, there is a chance of getting No Video when the monitor MST is set to "Off" or "Primary".

• The following "Hot Keys" will change the MST settings to MST Secondary. You are basically changing the monitor’s Display Port modes from DP 1.2 to 1.1Press any key (excluding power button) to show the following dialogue box "There is no signal coming from your computer"
• Press any key again and the "input source" menu will appear.
• Press the green check mark (√) button for about 8 seconds and the following dialogue box will appear, "Set MST option to secondary"
• Press the green check mark (√) again the DP mode will change from DP 1.2 to DP1.1
• The monitor is now set to MST secondary and Resolution will be 3840x2160 @30hz."

After some power down and up of the monitor, finally the monitor could detect signal and work.

One thing I noticed is, the previous display(in macOS 11.2.1) settings in the macOS > Display settings were all gone. I needed to reconfigure things about font size, etc.

Hi!

I have a Asus ProArt PA279CV and Mac mini M1, and I managed to connect them with the USB C cable provided with the monitor. On the Asus website (https://www.asus.com/Displays-Desktops/Monitors/ProArt/ProArt-Display-PA279CV/HelpDesk_BIOS/) there is an upgrade for the firmware of this monitor that fortunately solved all the problems it had with Mac M1 computers. Now I can have two monitors connected one to the hdmi port and the other to the usb C port without any types of adapters, just plug and go.

Solution found to the problem of MacOS Big Sur not recognising an External Monitor via the USB-C port of a brand new iMac (which persisted with two brand new Apple Thunderbolt-2 to Thunderbolt-3 adapters): swapping a different adaptor (made by Choetech, purchased from Amazon) and the external display now works perfectly again even under MacOS 11.2.3. Phew!

The problem was assuming that Apple's adaptor would work...

The upgrade to OS 11.4 seems to have solved this issue. I still had to unplug my external monitor from power and plug it back in to get the laptop to recognize it, but it finally did. No problems since then.

Can you determine if your monitor supports DP 1.2 or higher? It seems that they disabled support for DP 1.1 with the bump to 11.2.2. I was able to enable DP1.2 on my dell monitor and was able to use usb-c to DP again!

Thanks!! After updating to 11.2.3 my USB-C connect LG 32UN880 didn't turn on anymore, so I tried unplugging the power cable from the display itself and did made my monitor turn on again!! guess maybe it it has todo something with the power passthrough charging?!? Maybe someone has an idea about that?

Try the following:

Reset NVRAM or PRAM on your Mac - Apple Support

How to reset the SMC of your Mac - Apple Support

Unplugging power supply and plugging back in immediately solved the problem for me.

Plugging off the power cable of the monitor and plugging in again worked for me as well.

Same issue here. Surprisingly though the following workaround seems to help: I put a Delock usb-c to VGI/HDMI/DVI switch port between my mac and the monitor. the monitor is now attached via HDMI to usb-c adapter to my mac.

my set-up:

mbp 2017 132

bigsur 12.2.2

HP Elite E324q 31.5" external display

I have this exact same issue.

Macbook Air M1

Monitor: HP U28

After the Macos 11.2.2 update the monitor doesn’t recognise video signal coming from the macbook via the USB C cable.

The USB hub inside the monitor continues to work however and the macbook is getting charged just fine.

I also tested multiple USB C and Thunderbolt cables and did reset the monitor to its factory default settings. This didn’t help.

Same problem here.

The USB-C ports of left side does not works more for video. If I use ports on the right works. It issue started after update to version 11.2.2 (20D80).

I tried exec resets mentioned by https://discussions.apple.com/thread/252502798?answerId=252502798021#252502798021 but without success.

MacBook Pro (15-inch, 2018) with touch bar

Same but I needed a Windows PC in order to update the firmware. You too or there is any other solution ?