Mac mini M1 - LG Ultrafine 5k display wake problems

Big Sur 11.1

This release also addresses the following issues:

• 
  
• Bluetooth connection status was not displayed in Control Center
• 
  
• 
  
• Reliability of unlocking your Mac automatically with your Apple Watch
• 
  
• 
  
• Trackpad scrolling speed may be faster than expected on MacBook Pro models
• 
  
• 
  
• LG UltraFine 5K Display may incorrectly display at 4K resolution on Macs with M1
• 
  

I have had a very similar experience (with the M1 Mac mini and the LG Ultrafine 5K).

I have had to resort to disconnecting the cable and reconnecting which has worked sometimes to get the display to wake up but not every time (requiring a force shutdown on the Mac mini).

I have also had the display wake after sleep but the video output shown on the display is garbled. I need to take a picture when it happens next, but the content shows with almost like a vertical interlace with stair step distortion. Hard to explain but nothing in the UI would resolve this (force a resolution change etc). This required a disconnect of the cable and reconnect - which then returned the display back to normal.

I've had the same issue. With my pre-existing LG Ultrafine 5K, which has worked flawlessly with my macbook pro but using the same cord on the M1 Mini it blanks out even while I am using the mouse or keyboard and comes back only for a few seconds at a time. Connecting toa 4K display (where my old mini was) works fine connected with an HDMI. While connected with the HDMI to the 4K, the M1 Mini never even sees the Ultrafine. Also, if I unplug the Ultrafine (with out the HDMI/4K connected) from the M1, it will not see it/wake the screen when I plug it in. Quite annoying. I assume LG and/or Apple will ultimately come up with a fix, but it simply cannot work now

Seems that more M1 machines have some trouble with the 5K model. My MacBook Pro also has some issues with the LG 5K. It refuses to use resolutions above 2880x1660... My wives 2016 MacbookPro still works fine with it. Only with switcheresx I can tweak it to run higher resolutions. LG's screen manager also does not recognize my LG Ultrafine 5K on my M1. The old MBP model has no trouble at all.... Hope there will be an update soon... Good luck!

I have had a very similar experience TOO (with the M1 Mac mini and the LG Ultrafine 5K).

M1 Mac mini with 5K LG will be only working in 4k mode when wake from sleep. After boot it working in glamour 5K resolution but when my mini sleep, then i wake it up it will only work in 4k mode. I have to reboot my Mac mini to get 5k mode again. Looks like M1 Mac has a lot compatibility issues on external display connection.

Adding my name to the growing list of woes with an M1 Mac mini (fully spec'ed) and an Ultrafine 22". Display occasionally has trouble waking up after the M1 goes to sleep no matter what cable I use (using original Apple cables), and unplugging/plugging back the monitor seems to work. The display sometimes also stops responding to volume or brightness input, and in rarer cases even goes black for a second when exporting complex files from Final Cut Pro 10.5. LG's ridiculously-useless app does nothing-- can't reset, upgrade firmware, it can't even recognize the monitor. I should mention this is a barely-used, almost new, monitor.

Hoping Apple can release a patch for this.

I've been able to get the Ultrafine 5K to work with my M1 at full res. Sound and video cam all work fine. I've seen the blank out issue maybe once or two a day but no big issue, just a few secs of lost productivity. I set my display to not shutoff for 2hrs and seems all is fine. However, I haven't been able to get a Ultrafine 4K I have to work with the HDMI port. Tried all sorts of connectors but none have worked. Appreciate if anyone knows how to get the Ultrafine 4K to work with the M1 HDMI port.

I have the exact same issue. What I have also noticed is when I wake up from sleep, the UltraFine 5K is detected as a 4K monitor in About this Mac > Displays complete with the 3840x2160 pixel res.

Unplugging the monitor and reconnecting resolves.

Why isn’t there more information on this? MacBook Air M1 having same problem with LG ultrafine 5k. Only being shown in 4K (3840) when I can get it to work at all. Something is up with the display output with their new machines.

I’m sure it will get fixed. Question is when. Just slightly annoyed to buy a new machine and a monitor (one they stand behind) and it doesn’t work. Wondering if I should return the monitor given I’m still in the return window.

Similar issue with my M1 Mac Mini and my LG 5K ultra fine. The workaround for the reversion to 4 K is to sis and putting the monitor to seek under Energy savings settings. Once I did that the System responds quickly to mouse or keyboard activity to turn the monitor back on, and it stays in 5K. I hope a complete fix is forthcoming from Apple.

Hmmh I have also Problems with M1 and LG 5k. It goes dark randomly for 1-2 seconds. very annoying as I do a lot of live videos. The support in Germany here was unaware of the problem. They said I should try with a new user as it should be a software problem. But I used the same software with my former Mac mini without problems.

I have a similar problem. When mini wakes up the monitor reverts to 4k NOT 5K resolution. I have to disconnect and connect the cable to the monitor and I get my 5K back. I found a workaround by going to system preference>energy saver and checking prevent computer from sleeping. Apple Tech said this will not hurt the computer. Since they couldn't figure out why this was happening, after 6 phone calls, they decided to send me a new Mac Mini and Apple thunderbolt cable. We will see what happens. The next step will be calling LG support.

I'm having a similar problem with my monitors.

They connect fine on startup and operate perfectly - until and unless my machine goes to sleep. Then one or the other monitor will freeze - and/or show strange psychedelic colors - and I have to do a hard restart on the computer to get things back. Right now, the only solution seems to be not letting the computer sleep, and not letting the disks go to sleep. When I do this, everything works fine - the monitors look great (especially the Acer Predator!) with better color and detail than I've ever managed from my aging MacBook.