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Question: Big Sur 11.1 External Display Issues!

I've installed macOS Big Sur 11.1 right after it launched today. My mistake lol


Unfortunately, I noticed my Type-C ports no longer recognize my two external monitors. I'm using HDMI to Type-C. So far my troubleshooting is as follows:

  1. PRAM reset. This seemed to help until I locked the display. Once unlocked via Touch ID, the True Tone went off and one of the two monitors went out and will no longer connect. Woot. Normally, when connecting an external display, the screen goes black then back on, however, the screen short-of lags and then doesn't ever detect an active connection.
  2. SMC reset. This actually didn't help at all... :(
  3. Fresh install, same issues.


Any suggestions?

MacBook Pro

Posted on Dec 14, 2020 3:44 PM

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Dec 16, 2020 6:56 AM in response to iTimC21 In response to iTimC21

Having same issue. MacBook Pro 16 connected to 43in LG 4K display via usb-C cable.


Before 11.1 - no issues. display correctly identified and able to display native 4k resolution with HDR enabled

After 11.1 - display not recognized correctly. Native resolutions incorrect. Max resolution 1080p on a 4k display.


Reset PRAM - no change

Reset SMC - no change


Temporary workaround. Using LG on screen controls, change display port version 1.4 to version 1.2. After that I am able to get full 4k from the monitor but I lose HDR. The display is still incorrectly identified as 27 in screen.


Sounds like something changed between 11.0 and 11.1 that affects displays. Apple needs to address this ASAP

Dec 16, 2020 6:56 AM

Question marked as Helpful

Dec 16, 2020 4:52 AM in response to iTimC21 In response to iTimC21

Similar issue on my end:


23" Apple Cinema Display connected via DVI adapter is no longer recognised. Display works fine on my other MacBook Pro running previous version of Big Sur.


The port does register the adapter being plugged in - when I plug it in, the mouse cursor drags and becomes unresponsive for a few seconds.


What's going on?


Dec 16, 2020 4:52 AM

Question marked as Helpful

Dec 17, 2020 3:13 AM in response to b_mikhael In response to b_mikhael

Your setup is very similar to mine and same issues. 2020 16" Macbook Pro connected to BenQ 27" 4K@60hz via CalDigit thunderbolt dock.


Before big sur 11.1 = No issues whatsoever

After = Any resolution above 1080p forces refresh rate to 30hz max


FYI to manually switch between specific resolutions and refresh rates:

• System settings > display settings

• option + click on 'scaled' option

• Click "show low resolution modes" to display refresh rate list


How does a bug like this make it through QA I'll never know!

Dec 17, 2020 3:13 AM

Question marked as Helpful

Dec 16, 2020 2:59 PM in response to iTimC21 In response to iTimC21

I've a similar issue, I've two external monitors connected to my MacBook Pro 2019, the first monitor is Benq EW3270U connected to a CalDigit powered hub via DisplayPort, the second monitor is Benq SW271 connected directly to a USB-C port on the laptop using a USB-C to a DisplayPort adapter, both monitors are 4K@60Hz, all the cables used can handle the throughput requirements, the hub and adapters can handle it too, the setup used to work fine on MacOS 10.x, since I updated to Big Sur, the second monitor which is connected directly to the computer using the USB-C to DisplayPort adapter shows 800x600 resolution!

Dec 16, 2020 2:59 PM

Question marked as Helpful

Mar 18, 2021 12:31 PM in response to gaolbird In response to gaolbird

I have been involved in this Discussion Group almost since day one. Please look at the name of the Discussion Group. This is about External Displays not working on Macs, as they should, since the introduction of Big Sur 11.1. This covers MacBooks, iMacs and Mac Minis. All Mac Models (MBs, iMacs & Mac Minis) are affected in Big Sur whether intel based or M1 based. More importantly, Apple seems to be doing nothing about the issues. This is where we should be focusing our energies.

Mar 18, 2021 12:31 PM

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Question marked as Helpful

Dec 16, 2020 4:52 AM in response to iTimC21 In response to iTimC21

Similar issue on my end:


23" Apple Cinema Display connected via DVI adapter is no longer recognised. Display works fine on my other MacBook Pro running previous version of Big Sur.


The port does register the adapter being plugged in - when I plug it in, the mouse cursor drags and becomes unresponsive for a few seconds.


What's going on?


Dec 16, 2020 4:52 AM

Reply Helpful (7)
Question marked as Helpful

Dec 16, 2020 6:56 AM in response to iTimC21 In response to iTimC21

Having same issue. MacBook Pro 16 connected to 43in LG 4K display via usb-C cable.


Before 11.1 - no issues. display correctly identified and able to display native 4k resolution with HDR enabled

After 11.1 - display not recognized correctly. Native resolutions incorrect. Max resolution 1080p on a 4k display.


Reset PRAM - no change

Reset SMC - no change


Temporary workaround. Using LG on screen controls, change display port version 1.4 to version 1.2. After that I am able to get full 4k from the monitor but I lose HDR. The display is still incorrectly identified as 27 in screen.


Sounds like something changed between 11.0 and 11.1 that affects displays. Apple needs to address this ASAP

Dec 16, 2020 6:56 AM

Reply Helpful (30)

Dec 16, 2020 2:41 PM in response to iTimC21 In response to iTimC21

Same issue here. I'm using a LG Ultrafine 5K and a LG IPS224 Full HD connected to a MacBook Pro 16. The Ultrafine connected via Thunderbolt 3, and the other one using HDMI to Type-C. No issues til I updated to 11.1, when the Full HD display stop working (SMC and PRAM reset did nothing). The Ultrafine still works.


I hope Apple fix this ASAP.

Dec 16, 2020 2:41 PM

Reply Helpful (1)
Question marked as Helpful

Dec 16, 2020 2:59 PM in response to iTimC21 In response to iTimC21

I've a similar issue, I've two external monitors connected to my MacBook Pro 2019, the first monitor is Benq EW3270U connected to a CalDigit powered hub via DisplayPort, the second monitor is Benq SW271 connected directly to a USB-C port on the laptop using a USB-C to a DisplayPort adapter, both monitors are 4K@60Hz, all the cables used can handle the throughput requirements, the hub and adapters can handle it too, the setup used to work fine on MacOS 10.x, since I updated to Big Sur, the second monitor which is connected directly to the computer using the USB-C to DisplayPort adapter shows 800x600 resolution!

Dec 16, 2020 2:59 PM

Reply Helpful (6)
Question marked as Helpful

Dec 17, 2020 3:13 AM in response to b_mikhael In response to b_mikhael

Your setup is very similar to mine and same issues. 2020 16" Macbook Pro connected to BenQ 27" 4K@60hz via CalDigit thunderbolt dock.


Before big sur 11.1 = No issues whatsoever

After = Any resolution above 1080p forces refresh rate to 30hz max


FYI to manually switch between specific resolutions and refresh rates:

• System settings > display settings

• option + click on 'scaled' option

• Click "show low resolution modes" to display refresh rate list


How does a bug like this make it through QA I'll never know!

Dec 17, 2020 3:13 AM

Reply Helpful (7)

Dec 17, 2020 3:35 AM in response to mwventre In response to mwventre


Temporary workaround. Using LG on screen controls, change display port version 1.4 to version 1.2. After that I am able to get full 4k from the monitor but I lose HDR. The display is still incorrectly identified as 27 in screen.


Could you explain these instructions in a bit more detail?


Presumably in the monitor OSD settings (on the monitor controls?). I only seem to have the option for DiplayPort1,2 enabled = yes/no.

Dec 17, 2020 3:35 AM

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Dec 17, 2020 8:01 AM in response to fuzzylogic_uk In response to fuzzylogic_uk

I think this really depends on the make and model of your display. I'm using a fairly new display that has direct usb-c to usb-c capability. Within the settings on the display's OSD I am able to select which version of the display port it uses. My options are 1.4, 1.2, or 1.1. Factory default is 1.4. This is the version that allows for HDR and what I was using prior to Big Sur 11.1 with no problems whatsoever. Immediately after installing the 11.1 update the display wasn't recognized properly and the OS showed it's maximum native resolution to be 1080p and sometimes 800x600 depending on what sequence I plugged and unplugged the connection. The only way I got it back to 4k was by changing that setting directly within the monitor OSD. However, as I mentioned the OS is still incorrectly identifying the make and model of the display.

Dec 17, 2020 8:01 AM

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Dec 17, 2020 3:43 PM in response to iTimC21 In response to iTimC21

I'm having the same issues. Big Sur 11.1 on a 2019 MBP 16".


Connection is USB-C to an LG 4K 32" which has been working fine for a couple years @ 60hz. After the update, the monitor has a bevy of issues including wrong resolutions, wrong refresh rate, and variations of that depending on what order I plugged in the cable and what color t-shirt I am currently wearing.


Reset PRAM and SMC probably 80 times at this point. I even swapped the LG provided USB-C cable with an Apple Thunderbolt 3 cable which had the same issues.


It's likely a software thing and I've seen enough reports online such that I'm surprised that this issue survived the beta period.

Dec 17, 2020 3:43 PM

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Dec 17, 2020 6:54 PM in response to obscurelyfamous In response to obscurelyfamous

Hello. I am having issues with Big Sur 11.1 as well.


I have a Dell WD19 docking station and two brand new Samsung LS22T350FHNXZA 22inch running at 1080p. They work perfectly with Intel MacBook Pro 2019 and MacBook Pro 2014. I got a Macbook Air M1 and when I was on Big Sur 11.0 it would mirror the two external monitors and when I upgraded to Big Sur 11.1 none of my monitors work.


Congratulations Apple for making my dual monitor setup obsolete.

Dec 17, 2020 6:54 PM

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Dec 17, 2020 10:52 PM in response to kosta205 In response to kosta205

Since I can’t edit my comment, I’ll add to the thread:


i’m seeing two issues:


  1. Displays being detected incorrectly, leading to scaling and refresh rate issues;
  2. Displays not being detected full stop.


All these issues seem to be on 16” MBPs.


@mwventre was able to circumvent the first issue by forcing the resolution and framerate from the display onboard menu on an LG display.


How does such an issue get through a public beta...


Dec 17, 2020 10:52 PM

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Question: Big Sur 11.1 External Display Issues!