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DaveXX

macrumors regular
Original poster
Jul 17, 2020
128
31
I have a LG 43 UN 700B 4K HDR Monitor. But after the latest update to big sur 11.1 its no longer possible to use 4K Resolution... even with SwitchResX the resolution is unavailable....

I restarted and plug / unplug the monitor already several times but it will not work...

Somebody else had a similiar problem?
 

andrewsyd

macrumors newbie
May 10, 2012
10
1
Yes I am having the same issue with my BenQ PD3220U 4K Monitor and 16" MacBook Pro.

Once the update to 11.1 finished, my MBP (with the lid open) didn't even recognise the monitor again at first. Then when I unplugged the thunderbolt cable and plugged it back in, the monitor was detected but only at 1080p.

Played around with the Display settings in System Preferences for a few mins but couldn't get it to list any higher resolutions. Then I decided to turn off the monitor and back on. It worked (though I had to reselect the higher resolution manually).

But once I rebooted, the resolution went back to 1080p and I haven't been able to get it working again. Very annoying to say the least.
 
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DaveXX

macrumors regular
Original poster
Jul 17, 2020
128
31
I tried yesterday everything...
Have a MBP 16 with 5600m and TB cable.
Tried different TB cable, usb-c to Display Port (which was not working), i checked with my Dell Workstation that monitor is still ok (which is the case), repair installation....

Do you have as well a 5600m? Maybe its a driver issue?
After a lot of tries at least i have the display running at 3360x1890 with 30hz (makes no sense at all).

The worst thing is that there is no way to make a downgrade... its my main working computer and i cannot work 8h a day without external monitor... :oops:
With 11.0.1 there was no issue it just started after the update. As you can see at the screenshots everytime i un/plug the display it show different supported resolutions...
 

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Marc G.

macrumors newbie
Oct 25, 2008
22
3
Yes I am having the same issue with my BenQ PD3220U 4K Monitor and 16" MacBook Pro.

Once the update to 11.1 finished, my MBP (with the lid open) didn't even recognise the monitor again at first. Then when I unplugged the thunderbolt cable and plugged it back in, the monitor was detected but only at 1080p.

Played around with the Display settings in System Preferences for a few mins but couldn't get it to list any higher resolutions. Then I decided to turn off the monitor and back on. It worked (though I had to reselect the higher resolution manually).

But once I rebooted, the resolution went back to 1080p and I haven't been able to get it working again. Very annoying to say the least.
I have the same monitor connected via Thunderbolt 3 to my 16" MBP 5500M.

4K works for me after manually selecting it in System Preferences, however with the lid closed, the UI is laggy and has very low FPS. If I use it as an extended display with the lid open, everything is fine.

How can Apple release such buggy software? Incredible...
 
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sadmin

macrumors newbie
Dec 15, 2020
1
2
I had the same problem and when finding a solution it got worse so that the resolution could only be set to a maximum of 720p. I tried a PRAM reset, no improvement. I tried SwitchResX (don't do it please): you couldn't read anything anymore because the high resolution was downscaled to 720p.

Only a SMC reset helped and remains stable even after a reboot.
However, you have to make the monitor settings twice, with the lid open and closed.

16" MBP 5500M with LG32UD99-W 4K, Thunderbolt 3

(shut down the MBP, hold down the power button until it restarts the second time (or turns off))
 
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DaveXX

macrumors regular
Original poster
Jul 17, 2020
128
31
Unfortenately SMC Reset will not help here :confused:
I tried already several times but the result is in the end i have 720p instead of 4K30 or at least 1080p....

Does someone have 5600m with LG or other TB/USB-C Displays?
 

jasonadt

macrumors newbie
Dec 15, 2020
4
2
I'm experiencing a similar problem ever since updating this morning to 11.1 (everything had been working fine on 11.0, before updating to 11.1). I have a 16" MBP and my external monitor is a Philips Brilliance 346P (Ultrawide) connected via USB-C. Now I'm only able to get 1080p resolution from it (I've tried everything to no avail).

Has anyone found a fix for this or heard anything from Apple?
 
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coffeeplease

macrumors 6502
Sep 28, 2019
408
271
Interested in knowing if anyone who has installed 11.1 and has their external 4K monitor working. This is a productivity nightmare.
 

codingclass

macrumors newbie
Dec 15, 2020
1
0
I have the same problem. Maybe you can replug the thunderbolt wire to temporarily solve fix it.
 

DaveXX

macrumors regular
Original poster
Jul 17, 2020
128
31
I already tried unplugging/replugging the USB-C cable (including into different ports) and it doesn't fix it.
i replug the cable maybe 30times until suddenly i had 4k30 (until next reboot). have now usb-c to hdmi adapter which is more stable working at 4k30 (should be 4k60). but better than 720p...

called today apple care and wasted some hours in the line but nothing except the usual process -> do smc reset, do nvram reset, add another user, send us log files....

I'm just confused that during beta this was not reported? so it will affect maybe just specific devices?

@jasonadt you have a 5600m?
 

skiabox

macrumors regular
Jul 27, 2010
160
98
Larisa, Greece
Same problem here.
I managed to change it back to 4k for once but I don't know how I did it.
And of course it does not keep the settings after a restart!
The monitor is a BenQ EW3270U
 

skiabox

macrumors regular
Jul 27, 2010
160
98
Larisa, Greece
Yes I am having the same issue with my BenQ PD3220U 4K Monitor and 16" MacBook Pro.

Once the update to 11.1 finished, my MBP (with the lid open) didn't even recognise the monitor again at first. Then when I unplugged the thunderbolt cable and plugged it back in, the monitor was detected but only at 1080p.

Played around with the Display settings in System Preferences for a few mins but couldn't get it to list any higher resolutions. Then I decided to turn off the monitor and back on. It worked (though I had to reselect the higher resolution manually).

But once I rebooted, the resolution went back to 1080p and I haven't been able to get it working again. Very annoying to say the least.
Thanks for the turn off the monitor trick!
It worked!
Of course now I will keep the MacBook Pro 16 on till the next patch!
 
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andrewsyd

macrumors newbie
May 10, 2012
10
1
Thanks for the turn off the monitor trick!
It worked!
Of course now I will keep the MacBook Pro 16 on till the next patch!
No worries ☺️

I finally got it working again the next morning. Now I'm too paranoid to reboot it 🤣
 

djlythium

macrumors 65816
Jun 11, 2014
1,039
1,435
Interested in knowing if anyone who has installed 11.1 and has their external 4K monitor working. This is a productivity nightmare.
Mine's working. M1 MBP with 11.1 to a Samsung Q50. No issues (aside from a 'slow to show image on screen' issue that was present before.).
 

jasonadt

macrumors newbie
Dec 15, 2020
4
2
i replug the cable maybe 30times until suddenly i had 4k30 (until next reboot). have now usb-c to hdmi adapter which is more stable working at 4k30 (should be 4k60). but better than 720p...

called today apple care and wasted some hours in the line but nothing except the usual process -> do smc reset, do nvram reset, add another user, send us log files....

I'm just confused that during beta this was not reported? so it will affect maybe just specific devices?

@jasonadt you have a 5600m?
I have a 5300m
 

DaveXX

macrumors regular
Original poster
Jul 17, 2020
128
31
the only thing which is working somehow here is the hdmi adapter with 30hz. the strange thing is if i plugin first the hdmi adapter (same monitor) and after that the TB cable i get often 4k30 as well...

Turning off monitor or other workarounds unfortenately are not working.
 

jasonadt

macrumors newbie
Dec 15, 2020
4
2
I've tried *many* times/combinations to turn the monitor on/off and unplug/replug the USB-C cable, I also tried restarting my 16" MBP with the monitor both plugged/unplugged and it doesn't make any difference for me :(
 
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philosopherdog

macrumors 6502a
Dec 29, 2008
651
423
Thanx for posting this. This is the kind of issue that is the reason I'm waiting for a good while before moving to big sur. I'm working 8-10 hours a day and these sorts of bugs are a deal breaker. I would recommend trying hdmi cables. They tend to be the least flakey.
 
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gdb420

macrumors newbie
Mar 5, 2013
5
2
Clean installed 11.1 on MacBook Pro 15"(2017) w/Radeon Pro 560, connected to Sony 4k tv by Apple USB-C AV adapter, everything worked normally with 3840x2160@60Hz
Both open lid dual display, closed lid external display only modes
 

tangfish

macrumors 6502
Sep 12, 2014
253
315
I came here to see if it’s safe to update, glad I checked before doing so.

Hope you guys get a resolution. In the meantime I will stick to Mojave!
 

DaveXX

macrumors regular
Original poster
Jul 17, 2020
128
31
took me nearly 1/2 day but i wanted to be sure... i created usb catalina installer and installed catalina on an external disk..
i restored the latest time machine backup so all programs are installed as before and now everything is back to normal Screenshot 2020-12-16 at 17.48.08.png

But what i don't understand:
1) Why nobody during beta test had this problem
2) why just a few have this problem... why not 1000 post about broken external displays?

(btw by rebooting to Big Sur 11.1 the display is at 1080p again so its definetely a software issue).
 
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shadrix

macrumors newbie
Dec 16, 2020
2
2
Damn, 😭I don't know what to do. I installed 11.1 yesterday without doing a backup. And now my monitor BenQ PD2700U doesn't work properly.

It's super weird, because first of all, my MacBook forgets the Arrangement of the Displays all the time. And at first, it was set to 1080p. There was no option to change any settings.

Thanks to DaveXX I just unplugged the cable dozens of times until I saw the "scaled" option again. Now, at last, I can set the resolution to 4k, however just 30Hz. This is kinda acceptable but what the heck.

When I don't use the monitor it all starts again. My MacBook just forgets the Arrangement of the Displays and I have to unplug dozens of times.

I cannot work like this. Any idea what I can do? Does it make sense to call Apple? Or do you know is it possible to downgrade to 11.0?
 
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