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Some Users Having External Display Connection Issues With macOS Big Sur 11.1 and 11.2

Hey Mac Peeps,

I am far from any kind of expert, but I found a solution that seems to work for me. I downloaded an app called SwitchResX. It's shareware, but it recognized my external monitor and allowed me to try different configurations and more importantly it seems, refresh rate combos and then - boom! My old faithful monitor came on!

As of this writing, my external display comes on from screen being off but not from sleep unless I reset the switchresX resolution that works. I'm still playing with the program. It definitely seems to be some kind of hardware/software/code line type if issue that apple needs to resolve. My current display resolution that is working is horrible, but tolerable. I love my new M1 Macbook Air, but they have to fix this soon.

SwitchResX is here: SwitchResX

Hope this helps someone.

Update: I was able to get a perfect resolution for my monitor by switching back and forth between to two resolutions. For example, my monitors best resolution is 1366 x 768, 60 Hz, but I cannot get to that unless I click 1024 x 768, 75 HZ first. Clicking it directly in the SwitchResX screen, does not work. I have to click the 1024 option first. I have not found a way to make SwitchResX force this resolution as the monitor is plugged in...

Update #2: Reading the SwitchResX Manual, it seems the inability to save/switch the resolution stems from SIP (System Integrity Protection) that is in the OS. I have disabled this from time to time in my old Macbook Pro before it died for various apps to work, but I'm a bit nervous to do so with Big Sur and the new M1. Will wait for a bit and do some research and see...
 
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I haven't had a problem in months. The "Fix" for me (Your Milage May Vary™) was to purchase the larger 61w Power supply from Apple. I've had NO problems since then. I was noticing when it wouldn't wake up or connect it was also saying it wasn't charging. I also made sure I used the Apple USB-C cables. Apparently many third party chargers and cables transmit less power, and when it was getting too low it would think it was unplugged and turn it off.
 
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Jasonondesign said:
I haven't had a problem in months. The "Fix" for me (Your Milage May Vary™) was to purchase the larger 61w Power supply from Apple. I've had NO problems since then. I was noticing when it wouldn't wake up or connect it was also saying it wasn't charging. I also made sure I used the Apple USB-C cables. Apparently many third party chargers and cables transmit less power, and when it was getting too low it would think it was unplugged and turn it off.
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Yes. personal experience too.

Apple’s USB-C Digital AV Adapter takes 18 W off the top. Interestingly a 3rd party (which in this case is a UGREEN 9-in-1 USB-C hub combo) only takes 7 W.

How do I know? I use a 100 W USB-C adapter and read how much the laptop was powered through the different adapters (via System Information).
 
MM07 said:
This is still an issue for my wife's M1 iMac. The second LG monitor, plugged in via DP to USB C, keeps waking every few minutes and says that it's going to sleep.

This was not an issue with a 27" iMac 2015.

It is updated to macOS 11.5.
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Still having this issue with macOS 11.6. It went away at some point in macOS 11.5.2, I think.
 
I'm having the same issue and it's beyond frustrating! I just purchased 2 LG Ultra Fine 4K monitors to use with my 2017 MacBook Pro (in clamshell mode) running Big Sur 11.6 and I'm having four distinct issues: 1) computer defaults the displays to 1080p & when I switch to scaled and select 4k resolution everything is SO small on the screen that it's not useable; 2) with monitors set at scaled 2304 x 1296 screensaver appears pixilated; 3) Monitors inexplicably go black while using the computer and I can't get them to restart unless I either detach and reattach laptop to power or restart laptop; 4) Screens rarely "wake" up after computer has been sleeping even though the laptop is awake - I have to detach and reattach power or restart laptop.

My set-up:
2017 MacBook Pro (used in Clamshell mode) in a Brydge vertical docking station (only ports are two pass-through thunderbolt 3 connections)

Apple power cord that came with the computer plugged into Brydge vertical docking station power MacBook;

Thunderbolt 3 cable (that came with LG Ultra Fine 4k monitor) connecting Brydge vertical docking station (i.e. MacBook) and Brydge Stone docking station (adds additional ports - ie sd card; HDMI; USB; thunderbolt 3, etc) - this docking station is also plugged in for power;

Thunderbolt 3 cable (that came with LG Ultra Fine 4k monitor) connecting Brydge Stone docking station to 1st LG Ultra Fine 4K monitor;

Apple thunderbolt 3 cable daisy chaining 1st LG Ultra Fine to the second LG Ultra Fine.

External Magic k
Keyboard and Magic Trackpad

Both monitors are plugged into the wall as is MacBook as is Brydge Stone docking station so this isn't a power issue.

If anyone has come up with a solution yet.....you'll be my hero!!
 
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Zebedee1968 said:
I think I have it sussed for now.

I spent a while researching the problem today.

I've managed to reduce the ridiculously high CPU utilisation thanks to the WindowServer process by resorting to using the MacBook Pro in clamshell mode. With the external display connected via either USB-C directly or DisplayPort via the Thunderbolt dock, I have theoretically reduced the average utilisation to under 10%.

I now have a 2020 16" MacBook Pro connected to my LG 4K monitor, able to support 2160p at 60Hz refresh rate without bringing the entire system to its knees. That means I've had to ditch using the built-in display on the MacBook, but that's no terrible hardship, as I can use multiple desktops, as well as a far higher resolution display.

It's not a solution to the problem by any means, but it is a more than acceptable workaround.
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I'm having the same issues with my 2017 MBP in clamshell with two LG Ultra Fine 4K monitors (see my post from today 10/9/2021)...I am waiting for Apple to release the newest MBP in the coming weeks and intend to purchase. If I'm reading your post correctly, will this fix the black out issues and issue with defaulting the monitors to 1080p? When I set mine to run at 2160p at 60Hz everything is SO small on the screens they're not useable. Is everything super small still at 2160p with your 2020 16" MBP? Basically wondering if purchasing the newest MBP will correct all of the issues with the external displays. Thanks!
 
bobone said:
I've had odd issues with versions going back to yosemite on screens sleeping (the first version I noticed problems with dual monitors) I had the other problem - they went to sleep without me wanting them to. Caffeinated fixed that problem, but won't address the one you have. Since I went with the dual plugins, I have not had any further issues. A friend of mine has dual LGs connected via daisy chain, and he has no issues either (but note they are same maker, even if different monitor lines - 5K and 4K)

You could have something running in the background that's causing that issue. Screen sharing definitely does strange things if it thinks anything is connected even when it's not. I have a 10.13 system that is mostly connected to via screen sharing, and it does odd screen blips on its sometimes connected monitor. That system had issues with this all the way back to 10.10 as well that I know of, because that's when it became a secondary.
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I've got two LG Ultra Fine 4k monitors daisy chained with my 2017 MBP in clamshell mode and I'm still having the problem! Your friend is luck! Haha!
 
I am still having issues on my wife's iMac M1. Like I said before it is connected via DP to USB C. No issues on the older 2015 27" iMac.

Now on macOS 12.0.1 the issue persists.

We have the same monitors. I am not having the problem on my 2019 4k iMac.

Should I try HDMI to USB C?

Thanks.
 
So glad to find this thread. I've got a 13-inch MacBook Pro (sans Touch Bar) from 2016 which I use with two monitors & two USB-C to HDMI adapters. A few years ago the connection started inconsistently flaking out on one of the monitors when waking from sleep (usually the port that's closer to me). Would have happened on Big Sur and Monterey at the very least.

What I've found is the monitor is recognised as connected by the OS in System Information and under System Preferences > Displays, but the monitor doesn't have the signal. The problem appears to be the specific port that gets fried until I restart the computer (since if I swap the two cables I have it's the same port affected), or unplug and replug repeatedly and get lucky. The USB-C charging on the adapter still works, so the USB-C port on the computer isn't completely dead.
 
This affects my new MacBook Pro 2021 (M1 Max) along with my work MacBook Pro 2019 16" (Intel Core i9/AMD Radeon Pro 5300M).

Both run Monterey 12.0.1 (21A559) and connect to an LG UltraWide 38WK95C monitor, each via a separate Anker USB C Hub (HDMI port from the hub). The new MBP has an HDMI port, using that directly has the same problem.

The new MBP replaces a 2015 model that was connected via a DisplayPort to HDMI cable, and was unaffected.

The only reliable workaround is to either open the machine (difficult for me because I don't have enough desk space for two open Macs and an ultrawide monitor, so the Macs are in a vertical stand), or to unplug the USB-C and re-connect. It's a bit worse for the 2021 model with direct HDMI connection - unplugging the HDMI and reconnecting doesn't solve it, I have to open the lid.

I am going to report it to Apple customer support. I dread to think what kind of "turn it off and on again" routines they'll ask me to go through, but I hope that every customer reporting the issue will give them better visibility of the problem.
 
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Ok so the Apple chat support was useless; like all chat support in my experience it's getting increasingly difficult to tell the difference between bot and overworked human who is trying to keep several chats going concurrently. I gave up and waited until I had time to call.

Today I talked to Apple phone support and they were much more helpful and focused on the issue, putting me through to second line support and digging into the issue more deeply but without the "turn it off and turn it on again" rigmarole. Actually it helped my case that I mentioned the problem affects two Macs (2019 and 2021) but not the older one (2015), because I was told otherwise they might have suggested a hardware fault along with an OS factory reset to confirm it.

I was advised to try updating the monitor firmware although it's not clear to me at all if the firmware is updatable on my model, but I will need to talk to LG about that. Apparently many firmware drivers update the monitor automatically over HDMI's data channel.

Anyway, the main thing is the support technician has found and upvoted something related on their internal systems, and for that I'm grateful and consider it worth the time. I would suggest if anyone has half an hour to spare that it's worth doing the same.
 
I am still seeing this problem.

Some backstory. First I fixed the problem for a LG 34wk95u-w monitor, working in Clamshell mode with charging over just one Thunderbolt (USB-C) cable. I had to use a weird "hack" to enter the Mac while not in sleep mode yet still connected to the screen, and the only way I could do that was by using Teamviewer to go into the mac, there I could change the display settings to a value that was valid for the LG 34wk95u-w monitor.

Fast forward to today. Now I have problems with the existing monitor that I used, a DELL monitor running on 1920x1080p, where it refuses to display anything anymore when I connect the Mac to it using Apple Multimedia adapter and HDMI. I assume that this happens due to invalid screen resolution is stored in the memory of the Mac and that the Dell monitor tries to use the address that was configured for the LG monitor.
 
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Clix Pix said:
No issues here with a 15" 2018 MBP connected to an LG 4K Thunderbolt 3 display. The connection is direct between display and computer, using the supplied Thunderbolt 3 cable, with the display's other cable and power adapter plugged into a surge protector, and everything is working as usual.

I also have a 13" M1 MBP but have not connected it to an external display since I haven't needed to do that, as it is more of a secondary machine rather than the primary one I use for editing photographic images and such.

Both machines have been on Big Sur 11.2 for the past couple of days.
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LO HE SOLUCIONADO!!
Probe una infinidad de cables, pero lo único que ha funcionado fue:
Desactivar las actualizaciones automáticas y espere a que exista una para la Mac.
Antes de empezar la descarga he desconectado todo, excepto el cable que conecta al monitor, sin fuente de poder nada.
Inicie la instalación de la actualización una vez finalizo ojo sin desconectar el monitor funcionó el sonido desde el monitor

Ahora tengo miedo de apagar la computadora, porque tal vez deja de funcionar me he dado tantos golpes de cabeza que no quiero perder el sonido de nuevo.

I SOLVED IT!!
I tried a myriad of cables, but the only thing that worked was:
Turn off automatic updates and wait for one for your Mac.
Before starting the download I have disconnected everything, except the cable that connects to the monitor, with no power source at all.
Start the installation of the update once finished eye without disconnecting the monitor the sound from the monitor worked

Now I'm afraid to turn off the computer, because maybe it stops working I've hit my head so many times that I don't want to lose the sound again
 
Hi all, I have had this problem in the past with a previous update and managed to fix it (don't know how unfortunately) and now after the latest update this annoying issue is back.

Here are some details:
  • MacBook Pro 16-inch 2021, M1 Max
  • Monterey version 12.3 (this was the upgrade)
  • Monitor that is no longer recognised via USB-C (charge and/or display) - LG 32UN880
Anybody have the same issue with the latest updated and same monitor connection?
 
The problem is that when the operating system of the MacBook is updated, only the monitor must be connected.
 
Thanks Gabenc. Just an update, I managed to fix the issue.

The fix that worked for me was to restart the MacBook in safe mode with nothing connected. After restarting, I then plugged the charger into the laptop (MagSafe 3 Port). Leaving that in for about 5 minutes and making sure the laptop is charging, I think connect the monitor via USB-C (NB: the monitor was confirmed working via HDMI port from laptop prior). After doing this, the monitor and laptop responded to the connection and now my laptop is both displaying and charging via the USB-C connection.

Apple Support weren't able to help through their diagnostics but were interested in the fix nonetheless.

Hope it helps someone!
 
I have this issue EVERY day and it is almost becoming enough to make me switch to windows. Happens with HDMI or usb-c to hdmi either connected directly or through a hub.
 
My hassles went away when I bought a USB-C to DisplayPort cable (assumes you have a display port connector on your monitor).
 
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neil74 said:
I have this issue EVERY day and it is almost becoming enough to make me switch to windows. Happens with HDMI or usb-c to hdmi either connected directly or through a hub.
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Neil, first off this sucks.

Secondly, for my computer and my wife it turned out to be a power problem. Once the power drain got over a certain amount MacOS just cut off the monitor and "did odd things". The solution that's worked for me without a problem now for over 10 months was to purchase a BIG power supply. We were using 3rd party USB-C power supplies and cables, but even the 60W that ships from apple wasn't big enough, so I just bought the biggest one Apple offered (I think it was 120W although I'm looking now and see 140W) and used the USB cable that came with that adaptor to power the hub and all my problems went away.

I wish Apple detected this and flagged it so we were aware of what was happening, but it's possible this is actually a function of the hub where it prioritized powering the computer and if that draw got too much it just "gave up" on other ports... IDK... either way I hope this helps.
 
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