Mac Mini (M1) 2020, LG UHD monitor flickers on dark colours.

Try to set the the black stabilizer to 0 in monitor.

I also have the same problem with the same monitor and the M1 mac mini. I got in touch with a LG costumer representative and they told me that they think is a lack of software support from apple and they will contact apple, so drivers can be added on a MacOS patch... Im not sure how to solve this issue, and that patch could take forever... I hope someone could help with this issue...

Same issue with 24" DELL U2421HE (2020) and Mac mini M1 (2020).

Mine shows both vertical and horizontal flickering (though never in the same location at once). It seems to occur mostly with dark grey colors but happened with very light colors as well. Dark mode is close to unusable at this point as several areas on screen seem to be constantly in motion. It happens with both HDMI, native USB-C, and DisplayPort-to-USB-C.

It does NOT occur with my MBP13 2015 and MBP13 2017, both running macOS Big Sur 11.1. It only occurs on the Mac mini M1.

It does NOT occur on my old 23" NEC EA232WMI and Sony KD-55XF9005 TV (same cables). It only occurs on the newer DELL monitor.

I had two phone calls with Apple already but we could not find a solution. We tried everything from changing cables to power resets, resetting the monitor, and ultimately reinstalling macOS. I was told to wait for macOS 11.1 which I did but the problem persists. They did tell me though that there were issues in the graphics driver for M1 macs.

Even after several weeks and hours of tinkering I could not narrow down the cause (or at least a partial remedy). The presence and severity of the flickering seems to change depending on the colors visible on screen. For instance, opening the monitors OSD sometimes changed with flickering (for better or worse). It happens with only a single window open but sometimes changes when additional windows are visible (on top).

I found that tinkering with color modes sometimes brings improvement, especially when it results in affected grey areas to be displayed in a darker shade. However, with this I have seen several black screens when waking the Mac from sleep. So it's really more of an anecdote than a workaround.

While adjusting color modes I realized that my Mac apparently does not even drive the monitor with (s)RGB as it should (YPbPr). Afaik the latter is designed for TVs. Setting the monitor to RGB results in a purple screen. Apparently this is a known issue:

• https://discussions.apple.com/thread/250732856
• https://spin.atomicobject.com/2018/08/24/macbook-pro-external-monitor-display-problem/

Unfortunately, the (previously known good) workaround no longer seems to work on M1 Macs (see https://gist.github.com/adaugherity/7435890). Most likely not the root cause but I could imagine it's somewhat related.

All in all it's pretty annoying because it's not just an app that does not work but affects the whole UI. What's frustrating is that it seems to affect random displays so I cannot even order a replacement display without having to worry about a refund. All we can do is wait for Apple to locate and fix the issue.

Hi

Yes I have the same problem here! I just bought this LG 32" UN500 unaware of the problem.. but when there's dark shading on the Big Sur interface it will flicker between the dark and lighter shading.

In System Properties when I use the search bar, Big Sur will dim the interface (the icons will go dimmed) that's when this sudden light flicker occur to the overall display.

In the screen saver, if you select the Drift as screen saver, you will notice the flicker happen when its dimming from light to darker shades.

When hitting the Dashboard on the keyboard to pull up all my Application, the screen have this slight vertical dark bands happening all across the screen. This does not happen on any other monitor I own and even when the LG is connected to my old MacBook Pro

Im sure hope Apple is aware of this bug.. it seems like can be corrected with software update. As video professional its a bit annoying when I'm working and I know Iv should have researched better. But I love the LG and plan to stick to this monitor. Hopefully Apple will fix this problem soon!

Cheers!

Technica Studios

Hello, I have had the same problem with a 4k monitor. What I do is to move any open windows around and problem just go away..., I know its very annoying because wow Mac mini M1 so powerful but these little things are very sad.

currently experiencing this same issue on my M1 MBA with the LG 32UN500-w monitor. I have ordered apples multiport adapter to see if it will rectify this flickering issue. So far I have tried a usb-c to display port 1.4 cable and the HDMI cable that comes with the monitor along with an HDMI to USB c adapter and both flicker occasionally and always on dark screens or 4k content on youtube.

usb c to DisplayPort made no difference for me however after having to still use the Ben Q monitor while working (which I am going to return) I was copying 6TB of data from one external usb 3 drive to 2 others backing it up , I bought a usb-c to usb a 4 port hub and another drive . During the backup which took several hours the display stopped the flickering and was perfect , having ejected the drives and put all cables back neatly the flickering is back . I have 2 ideas what it could be :

1) when usb is under heavy under load flickering stops and this is internal within the m1

2) connecting usb drive earths the Mac mini in some way to mains and causes flickering to stop. Will grab a multimeter and test continuity between usb shield metal , cases and earth.

I just found this thread. I have also been having external monitor issues with my M1 MacBook Pro that I described here: https://discussions.apple.com/thread/252466851

I wouldn't say I have noticed the entire display flickering as a lot of people seem to describe in this thread, but I do get the vertical lines and I am also seeing faint patches of "horizontal static". It's most noticeable on darker backgrounds, but can also be detected on light backgrounds too. My monitor is the HP Pavilion 23xw connected with HDMI and Apples own multiport adapter. I am on macOS 11.2.1. This monitor works perfectly with all the intel based Macs I have connected to it. Additionally, my M1 Mac works fine connected to my Samsung TV using the same cables.

I'm curious if anyone has anyone yet tried the 11.3 betas see if it fixes the issue?

Yes, sadly I agree... it's really starting to look like it's some sort of hardware-related issue. Any it's not specific to HDMI and DisplayPort is equally affected. Maybe something weird going on at a silicon-level in the M1 processor/GPU?

For my PHILIPS 328E is red colour more prone to flickering than green. More flickering occurs when YouTube control panel is visible over your testing video. If I put monitor input to DP 1.1 things get better than if it is in 1.2 mode. If contrast or gamma setting pust some shades of red out of play than I can get no flickering at all but then some dark blue can trigger it again. And I am almost sure it is not the contrast issue. Play your test videos in a window and if flickering occurs, try to move the window around the desktop. You should be able to find a sweet spot with no flickering. Strange!!!! Look at my video if you haven't seen it before. I can stop and then trigger the flickering again just by moving a window with "critical" content. https://youtu.be/oK6-UEs60so

I have been through various things with Apple support on the phone and the next thing I have been asked to try is a complete clean install of Mac OS and then to run the Mini for a while without installing anything on it to see if the issue occurs. I am assuming someone else has tried this already - if so did it achieve anything?

I think that monitors with IPS panel work and monitors with TN panel have troubles, maybe because of their faster response time (1 ms instead of 4-5 ms). Anyway, I replaced my BenQ el2870u by a new HP U28 4K HDR with IPS and now I can finally enjoy the new mac.

Re-open a case again and again and again, like what I did until I was able to talk to a decent senior advisor. Initially, the AASP assigned to me gave a "properly working device" diagnosis on my unit but I vehemently challenged the diagnosis and elevated the concern to a senior advisor again and again.

Have your unit inspected first and when you have the unit delivered to the AASP, perhaps the "Geniuses" there would make some sense and I think it might be easier to elevate the claims while they have the unit at hand. Specify the model of the displays you are using, etc; give them a copy of the videos you have.

It is happening when the monitor can not display particular color. Please do the following adjustment, you may fix the issue.

choose Apple menu > System Preferences, click Displays, then click Color. Click Calibrate. Display Calibrator Assistant walks you through adjusting your display, then creates a calibrated color profile. 

OK I fixed my monitor!

Few days ago I purchased new Asus ROGXG27UQR and replaced my old 27" Dell on USB-c to DP connection. My old 24" 4K got new HDMI cable that was supplied with Asus monitor and now I have 0 flicker and 0 problems!

Now I can run my 24" Dell on 60Hz and Asus monitor on 144Hz without a single problem on my M1 mini and macOS Monterey is also working (I updated 1 week after switching cable so both 11.6 and 12.0 versions work).

To sum up: check your cables. They might work and everything, but they might have poor insulation and protection. Invest in good cables, specially HDMI seems to be very delicate. Also HDMI cable needs to support HDMI2.1as 2.0 has only 18Gbps and for 4K monitor on 60Hz it is needed around 19Gbps bandwidth. On 2.0 will work, but only in perfect conditions (probably if you use RGB instead yPbPr).