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

[skiabox]

This is crazy.
After sleep mode there is always a surprise waiting for you.
Now suddenly the external monitor started at HDR mode, when at the same time I have HDR mode unticked in the macos 11.1 settings!

 

[DaveXX]

if you are in default monitor mode and you press and hold the option key and go to scaled mode you get a list of all supported monitor modes.
(Will not help with this problem but it allowed me to choose 4k30 after I got the scaled option back)

i had this problem as well that my monitor switched suddenly to hdr but that’s at least better than just 720p 0r even worse

 

[andrewsyd]

I too am only getting 30 Hz on my BenQ PD3220U at 4K

 

[chris.h]

I have same issue. Macbook Pro 16 inch 2019, 5300M. LG UD99W 4k display. The first time it happened after the update it went back to 4k after a reboot. Now external display is stuck at 1080p though. Tried multiple reboots, powering cycling monitor, SMC reset. Nothing has fixed it yet.

 

[skiabox]

Today I woke up, I turned on my macbook pro 16 and all of a sudden the external monitor works fine!
Let's hope that it will keep that way!

 

[EPO75]

For me 11.1 just solves the washed out colours on my LG 27UL850 (4K) en also the signal USB-C loss, quite happy with it. On a Mac Mini M1.

 

[DaveXX]

For me 11.1 just solves the washed out colours on my LG 27UL850 (4K) en also the signal USB-C loss, quite happy with it.

it would be good to post which device you use... i currently see no pattern... so is just MBP 16 affected or any other device?
USB-C to HDMI seems no problem and if you use a docking station with DP it should work as well.

In general the problem will present with USB-C -> USB-C (TB) connections.

 

[skiabox]

I am using a usb-c to usb-c cable to connect my macbook pro 16 with the external 32 inch BenQ monitor.

 

[shadrix]

I'm using DP to usb-c. One thing helped me, but this is not a long-term solution was to change the Display settings on my monitor to DisplayPort 1.1 (it was set to 1.4).

 

[skiabox]

There are still problems with this update.
Sometimes there is no signal at all to the external monitor and the user should switch it off and on to get it to play again.

 

[andrewsyd]

I finally got 4K at 60 Hertz to work!
16 inch MacBook Pro
BenQ PD3220U 4k Monitor
macOS 11.1

Don't know if it's replicable or not but in case it can help any of you, here's exactly what happened:
1. With MBP already on but sleeping, plug in thunderbolt cable.
2. Resolution went to 1080p automatically.
3. Change refresh rate to 60 Hertz.
4. Signal on monitor dropped and I had to turn monitor off and back on.
5. Select resolution 3840 x 2160 (may need to option click 'Scaled')

 

[Serenissimo]

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?

I have the same problem with Macbook pro 16" and LG 32 4K USB-C connected. I downgraded to 11.0...The LG monitor is stuck at 30Hz instead of 60...

 

[Serenissimo]

The monitor LG 32 4K UL90 remains at 30 Hz also if the resolution changed...It's for sure a bug.

 

[Marc G.]

Has anyone tried if this is fixed in 11.2 beta 1?

 

[skiabox]

Has anyone tried if this is fixed in 11.2 beta 1?

They say that it is not fixed.

 

[Marc G.]

They say that it is not fixed.

I have just installed it and I have good news. I closed the MBP 16's lid and plugged in the Thunderbolt cable. I kept having 30Hz, however I went into System Prefs and clicked on "Default for this display", then my display went blank. I turned my display off and on again, and magically it works now at 4K and 60Hz. I hope it will keep working after I send it to sleep...

Edit: It was too good to be true, and after opening the lid and getting the extended desktop, the monitor went back to 30Hz. I haven't been able to replicate the above solution again.

 

[UltimateToybox]

I'm using DP to usb-c. One thing helped me, but this is not a long-term solution was to change the Display settings on my monitor to DisplayPort 1.1 (it was set to 1.4).

I just wanted to say that on my LG 27UL600 I changed to DisplayPort 1.2 and it's working at my scaled resolution at 60Hz. Quite an annoying bug though.

 

[DaveXX]

Changing DP Version at the display to 1.2 (instead of 1.4) will fix the biggest issue. But it will stay just at 30hz and show some weird information (Display is recognized as 8k display).

 

[DrewyMcDrewface]

Like everyone here has been saying, it seems to be a DisplayPort 1.4 issue. I switched my 3440x1440 144hz monitors over from DisplayPort to HDMI and I'm able to run them consistently at full resolution at 100hz (the maximum I can hit before exceeding HDMIs bandwidth limit) without any of the weird glitching that would occur whenever I woke up my MBP from sleep with DisplayPort (and even then, the best I could get was 60hz).

However for me switching the monitors to DP 1.1 via the OSD didn't fix the problem at all, so I had to just go buy another USB-C to HDMI adapter, which was fun.

Has anyone tried if this is fixed in 11.2 beta 1?

I also tried updating to the 11.2 beta and it didn't fix the problem, so now I'm back on 11.1 for whenever the real fix is available.

 

[eggtarts]

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...
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...

TLDR: Same Mac / monitor: Do not SMC reset cause it bricked the Mac into a chime loop. Apple LB/TID replacement. Don't install 11.1.

Yeah, I had this same issue too with same monitor and Mac. Got to 3360 x 1890 with HDMI and that was it.
Called support and did SMC reset, that completely bricked my Mac.

It was stuck in a chime loop non stop even with lid closed. No matter what combination of keys, the furthest one can go is internet recovery or partition. Once one selected the partition or network, and it restarts, it will be in a chime loop again.

Finally brought to genius and they couldn't even diagnose it wired cause it's completely bricked. End up replacing entire logic board and Touch ID.

 

[Serenissimo]

TLDR: Same Mac / monitor: Do not SMC reset cause it bricked the Mac into a chime loop. Apple LB/TID replacement. Don't install 11.1.

Yeah, I had this same issue too with same monitor and Mac. Got to 3360 x 1890 with HDMI and that was it.
Called support and did SMC reset, that completely bricked my Mac.

It was stuck in a chime loop non stop even with lid closed. No matter what combination of keys, the furthest one can go is internet recovery or partition. Once one selected the partition or network, and it restarts, it will be in a chime loop again.

Finally brought to genius and they couldn't even diagnose it wired cause it's completely bricked. End up replacing entire logic board and Touch ID.

Thanks for the detailed update. I have switched from USB-c cable to HDMI, stuck to 30 Hz but working ...

 

[DaveXX]

I got for free the original USB-C/HDMI Adapter from Apple. Now its working 4k60 without any issue. I can use my original PowerAdapter (Power Delivery) and have one USB-A Connection free... so in the end the solution is not so bad but i cannot believe a issue like this could go public.

I think finally its clear that the issue is related to Display Port 1.4 or USB-C connection using the DisplayPort Protocol 1.4.
So LG UltraFine Thunderbolt Display will not have the issue as well as any other DP 1.2 or HDMI Display.

DP 1.4 (even after so many years) is still not very common but especially Pro User with 4K60 (or more) and 10Bit using DP are affected which is unbelievable.

 

[MRrainer]

I though about updating (Mojave on 2018 i7 Mini, Eizo EV3285 display via USB-C).

Thank God I waited, again.

I hope they can get that fixed in 11.3, if they don't fix it in 11.2 (or in a post-11.2 update).

Just shows how conservative you have to be with Apple devices once you connect any 3rd-party device to it...

 

[skiabox]

I though about updating (Mojave on 2018 i7 Mini, Eizo EV3285 display via USB-C).

Thank God I waited, again.

I hope they can get that fixed in 11.3, if they don't fix it in 11.2 (or in a post-11.2 update).

Just shows how conservative you have to be with Apple devices once you connect any 3rd-party device to it...

I think that the problem is too big to not get fixed in 11.2

 

[omicronx9]

I got for free the original USB-C/HDMI Adapter from Apple. Now its working 4k60 without any issue. I can use my original PowerAdapter (Power Delivery) and have one USB-A Connection free... so in the end the solution is not so bad but i cannot believe a issue like this could go public.

I think finally its clear that the issue is related to Display Port 1.4 or USB-C connection using the DisplayPort Protocol 1.4.
So LG UltraFine Thunderbolt Display will not have the issue as well as any other DP 1.2 or HDMI Display.

DP 1.4 (even after so many years) is still not very common but especially Pro User with 4K60 (or more) and 10Bit using DP are affected which is unbelievable.

It most definitely is not unique to DP 1.4. My LG 32UD99-W won't work in 4k 60hz anymore and will only allow 30hz at 4k. Furthermore, everytime I unplug / replug it, it forgets itself and will only function in 1080p. The more I unplug it, the lower the resolution I can run it at. After 3-4 times unplugging it, it only runs in 720p 60hz. This bug is insane, it's unacceptable.