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

I have the same problem, my Mac mini arrived yesterday, plugged into my LG 32UN500 and I made a short time-lapse video on Final Cut Pro, part of the time-lapse has narrow vertical lines and induces a flicker when I play it in full screen. Glad at least that it isn't just me!

Is everyone going to return their monitors for a different one or wait to see if there is a patch in the works?

thanks

since my monitor was just bought I decided not to wait for the software fix (which should come but who knows when) and returned the monitor. Instead I bought a Benq and this one works well with no issues.

It’s a personal judgement, but ... Apart from the fact that one of them flickers and the second one does not, there is no perceivable difference in day to day use :) Specs say that LG has more nits (350) but at 60% Benq (300) is certainly bright enough. The speakers of both those monitors are abysmal. Google the reviews of Benq - they all say it’s a good monitor considering the price. I liked that LG has a white back, but I’m not really that much interested in watching the back or the monitor. A plus for Benq is USB-C with cable included. I’m connecting via hdmi but it’s nice to have a choice.

Exactly the same problem here , Mac mini M1 , 8GB , 256GB , connected to a BENQ EL2870U, both HDMI and usb c to DisplayPort do this when the content on the screen is dark for example set Final Cut Pro full screen empty , it makes the picture shimmer/flash rapidly and produce lines down the screen , certain blue colours do it too. The second you switch to something else like a web browser window it becomes normal. Did you find a fix?

My guess is this is a GPU issue :-( running 11.2 here too

From reading the above the BenQ I have is a TN panel, it would appear the M1 chips like IPS panels?

Same issue here. Mac mini M1 connected to BENQ EL2870U 4K HDR with HDMI (Belkin UltraHD 4K HDMI) and it flickers randomly or shows vertical lines.

It happens even worse when operating Garage Band.

Just switch to HDMI 2 plugin instead of 1 of the monitor, and it seems solved for now.

Sorry to hear that. Note that the output defaults back to ypbpr when changing any of the display settings within system preferences. Also, the issue can persist for a while even when unplugging the mac mini or when using another input. So maybe you were experiencing some leftover flickering?

Apologies for the incoming rant but I just have to express how frustrated and annoyed I am with Apple with this issue.

I decided tonight to spend some time documenting everything I've tried, take video/pictures of the flickering as it was happening, and then contact Apple support in the hope I might be able to have a reasonable conversation with someone and at least add another voice in the hope they can look into it.

As it turns out, none of the advisors were interested in looking at the information I had put together - they had me try the usual safe mode, power off for 30 secs etc... after which the advisor was about to arrange a return of the mac mini for review/replacement. Then a "senior" advisor stepped in and proceeded to fob me off, saying that because a second (totally different) monitor I have works, then it has to be my 4K monitor that at fault, despite me referencing this thread and everyone else here having the same issue, and the fact it works in Windows 100% with no issues. I got a load of copy and paste replies, and then was denied the replacement that the previous advisor had started to arrange! He wasn't interested in the slightest and was clearly following a script.

By far the worst support contact I've ever had with Apple. Since when did monitors work with one operating system properly, and not another? I've never seen it in 30+ years of using and building computers. Displayport and HDMI are standards, surely if an OS and GPU conform to those standards, it should work. This is a Mac/M1 problem in my opinion and Apple are just burying their heads in the sand, as usual.

I hope the rest of you can reach some sort of conclusion to this eventually, however for me the M1 Mac is going, I've spent far too much time trying to fix this. It's a shame I now have a rather bitter taste in my mouth from Apple support, my opinion of them has taken a sharp downwards turn tonight :(

Cheers

Has anyone tried new 11.5 RC macOS? I cannot try it as I have only one mac and it is my working horse machine. But would appreciate if anyone can try it. Because if it is not working I will issue replacement for my mac so warranty will remain and I will issue new replacements every month until they fix the issue or give us machines that will work. In worst case I will ask for refund if they release new updated macs with Mx chip.

I have this same problem. Vertical lines on dark colors.

At first, I had another problem with my 4k monitor: low frame rate. I bought a new dock and a new 8k Display Port cable and solved the frame rate issue. Smooth as an oiled billiard ball.

But the flickering and vertical lines on dark colors persists.

Monitor is an LG 32UN500-W.

Anyone with a fix or we need to wait for Apple to throw us a bone?

Visited the AASP to check on my M1 mac mini after MLB replacement. Flickering vertical lines on dark areas of the screen even in recovery mode still persist. Funny that even the AASP certified tech could not figure out a fix for these issues. They tried their own service monitors and they were able to replicate the issues even after the MLB has been replaced.

What a pain!!! Already talked to 7 senior tech advisors in the past 57 days since I first brought the unit to the AASP. Not one of them was able to help. They are just good in intimidating you and in making promises, etc. I've already asked for a replacement but nobody cared to have it replaced.

The AASP could not do anything else based on their service guide. 57 days and counting, 2 service reports uploaded...

Using Calibrate eliminated this issue for me immediately. My setup: Mac Mini M1 > HDMI > Philips 328E1

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.

I just stepped thru and saved the "calibrated" profile without making any changes, and it worked.

RichardEGrant wrote:

Okay, not 100%. Spoke too soon, but it corrected 50%+ where the issue occurred. It is variable depending on what images are on screen, even scrolling a webpage up/down makes it appear/disappear.

Turn off "auto anything" or "dynamic anything" or "special enhancement modes" on your display and only adjust brightness and contrast to get a pleasing image and test what happens. Also, if there is a sharpness adjust, set it to the middle of its range. If the display works without issue, then start turning these features back on one at a time until an offending display feature is found.

Several have resolved all their issues by disabling just one or two of those special features fixed everything.

Confirmed by a senior tech advisor (from my open case with Apple):

Apple warranty policy does not allow us customers to have our unit (mac mini M1) replaced. Repair, repair, repair it is.

Worse, you will have to wait when they decide to provide the replacement MLB; worse still, you will have to make the follow up with them; they will not come back to you with updates on your service request; worse still, there is no assurance of when and if the replacement MLB will fix the issue.

Our display woes are not recognized by Apple. I asked the service advisor if there's an internal memo about this issue or anything related to it and possible fix(es): there is none. Nada. So if there's no official issue, then there's no official fix. As simple as that.

Whatever "fix" we try here online, they are just temporary or are just band-aid solutions.

Another update from my end:

The replacement main logic board was still defective right out of the box! AASP replaced the other defective "replacement" MLB, and yet the replacement (2nd replacement) is also defective and it has worse issue out of the box--flickering lines are more obvious than before even on light areas (and dark areas of the screen). So that makes it 3 defective MLBs (original MLB, 1st replacement MLB, and 2nd replacement)--a strikeout!

May Apple have mercy on us!

Maybe, just maybe, the problem is with the internal power supply (prolly not supplying the correct voltage, amperes, etc. to the MLB? After 3 MLBs, problems still persistent (confirmed by my AASP). Apple did not replace the power supply.

I just don't know.