Big Sur 11.1 External Display Issues!

There is a nicely documented page that is keeping track of these external display issues here:

https://piunikaweb.com/2021/02/04/external-4k-monitor-issues-after-macos-big-sur-11-1-update/

Apple please fix!

1 - I had an MBP from around 2016, No issues with my two Apple Cinema Displays, using Apple DVI to Thunderbolt adapters. High Sierra and Catalina OS.

2 - In December 2019 I upgraded to a new MBP 13" and my displays were fine, using Apple and another brand of DVI to USB-C adapters. I did this as programs I needed had to have a 64-bit processor

3 - I exchanged it a few weeks later for the 16" MBP as I needed more ports. Catalina OS. Happy monitors.

4 - Updated OS to Big Sur 11. No issues

5 - Mid December 2020 I updated to Big Sur 11.1. Monitors were not recognized. Went through two Apple Senior Advisers, downloaded and sent multiple system reports.

6 - Big Sur 11.? - no change. I plugged the monitors into an older MacBooks Air using Catalina. No issues Updated it to Big Sur. No issues.

7 - I get my third Senior Advisor. Apple suggests an Apple multi-port adapter, USB-C to my MBP. tells me to hook up my monitor to the HDMI port. I get a Rocketfish DVI to HDMI adapter. I get color stripes, which change tones if I turn the monitor on and off.

8 - I borrow an Acer monitor from a friend. Connecting it via HDMI to the Apple adapter works.

I have an appointment Wednesday at my local Apple Store's Genius Bar. Not sure why I did this, but I figure it can't do more than waste some time.

So, it seems to me that something in the first Big Sur update disabled functionality in my MBP's USB-C ports. The questions are:

• Does Apple know what happened?
• Does Apple know how to undo it?
• Can Apple undo it?
• Ethically (hah!), does Apple owe everyone new monitors or new computers?

I've posted about this previously (since mid-December).

I have two 23" Cinema Displays with DVI connectors. Adapted to USB-C, they worked fine. Until Big Sur's first update.

After many tech calls and data report uploads I was asked to try an Apple USB, USB-C, and HDMI to USB-C adapter, connecetd to my monitor with a DVI to HDMI adapter.I got some signal, but only thin vertical color bars. If I turned the monitors off, then on, the colors changed.

Made an appointment via Apple with my local Genius Bar, with the idea I'd take in my MBP 16" (late 2019), adapters, and a monitor to see if the monitor "worked" with a different MBP. I got a call the day before the appointment from the Apple Store, and this got shot down. All I'd be able to do would be check my MBP in at a desk outside the store. I didn't see any point to this.

A friend loaned me an Acer monitor with HDMI inputs. Connected to my MBP with Apple's adapter - voila!

I bought a new LG 27" monitor (1980x1020, 75Hz max refresh rate 1ms motion blur reduction) as a test. It works.

For my needs, these specs are fine.

Now how do I get Apple to reimburse me for two monitors?

Found this in here https://displaysolutions.samsung.com/pdf/manual/3777/c49rg90_user_manual_eng.pdf

Not sure if this will help your case.

DisplayPort Ver.

Select your DisplayPort version.

― Incorrect settings may cause the screen to go blank. If this occurs, check the device specifications.

― If the monitor (when set to HDMI, DisplayPort1 or DisplayPort2) is in power saving mode or is displaying the

message Check the cable connection and the settings of the source device. or power saving mode activates,

press the JOG button to display the function-button screen and then select the button to display the On

Screen Display (OSD). You can select 1.1, 1.2 or 1.4.

― If setting the DisplayPort Ver. to 1.1, for the bandwidth limitation of the DisplayPort 1.1 protocol, the actual

maximum output refreshing rate of the display cards cannot achieve the level of 120 Hz.

― If you select 1.4, the monitor can support up to 5120 x 1440 @ 120 Hz.

― If you use 5120 x 1440 in DisplayPort source, you can't select 1.2.

HDMI Mode

Select the HDMI mode to use.

― The supportable device and resolution may differ depending on its version.

― When the version is changed, the screen may blink.

― Some high resolutions may not be supported due to the bandwidth limit in HDMI 1.4 protocol while HDMI

Mode is set to 1.4 or 2.0.

― When the setting is not appropriate, a blank screen may appear. In this case, check the specifications of the

device.

― Set HDMI Mode to 1.4 or 2.0 if sound from the connected DVD player is missing.

― This menu is not available when PBP is enabled

I'm still having the same problem with my external display (Dell U2715h, 2560x1440, 60 Hz), Big Sur (v11.3) and my 2017 27" iMac 5K.

• The display is connected to the iMac with a USB C to DisplayPort cable.

• If the display is powered on when I start the computer, there's no problem and it works.

• If I switch off the display while the computer is running, when I try to switch it on again the display doesn't shown any image. I could see that it's recognized by macOS in System Preferences, but for some reason the display doesn't detect any video signal.

• I can get signal again in the external display only if I restart the computer with the display powered on.

• I've tried reseting pram, SMC and different lower resolutions (1080p) but nothing works.

• Never had this problem before with the same display, same computer, same cable and same configurations in any of all previous macOS versions since 10.12.4 (Sierra) until 10.14.6 Mojave.

Quick follow-up, using a USB-C dongle and plugging in HDMI to monitor seems to work better and brings my audio back. Too bad I went out of my way to get a monitor with USB-C and USB hub only to have to Apple render it useless. Nice apple :smh:

If your Display Settings doesn't allow you to change brightness is there an on panel control?

I have two displays that my Mac has never permitted direct brightness control for on any OS (High Sierra, Mojave, Catalina, Big Sur): Samsung 4K tv and an LG 27UL600 monitor--both require on-panel or remote settings changes and these work just fine. Display settings brightness only recognizes my LG Ultrafine 4k 23.7" Have you searched to see if your BenQ has new firmware updates for Big Sur?

Download & FAQ | BenQ US

I’m using a LinkUp thunderbolt 3 hub and it is working very good. However, if I try another hub, the issue comes back.

I personally found LinkUp hub a good solution and in parallel I’m building up a desktop windows based PC. After 20 years of Apple I can’t accept as a professional, to waste months in fighting to solve the issues they introduced, doing nothing to get them solved!

I really don't think it's a hardware issue in my case. I have two Apple Thunderbolt 2 displays. Everything worked perfectly fine on Catalina. Once I installed Big Sur, the problem began. I got tired of not being able to use my two Thunderbolt 2 displays so I reloaded Catalina and again have no problems. My configuration is a MacBook Pro 16" 5600M with two Thunderbolt 2 Displays (daisy chained). I have no plans on upgrading to Big Sur or Monterey until this gets fixed.

@CamrenS, if you have a time-machine backup, you can go back I read. Although I re-installed macOS Catalina and started from scratch.... :-(.

(monitors are working well again :-))

Good luck!

Have you tried upgrading to the new macOS Big Sur 11.2.2 update?

Apple just released macOS Big Sur 11.2.3 today, Monday, March 8, 2021.

The switch to DP 1.2 solved the issue for me and my Benq from day one (11.1). But it's only a temporary solution.

To add in case it helps anyone else; using a HDMI - USB-C adapter (instead of the hub) offers a workaround (for me anyway).

Same monitor, BenQ PD2720U on M1 MacMini - with BigSur 11.1 - it can only display full 4k/60Hz if connected via HDMI port directly. Any other connection involving USB-C/TB3 drops to just 4k/30Hz: TB3 cable, USBC to DP, USBC to HDMI adapter.