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

Hi everyone,

I’ve received yesterday the new display for my new Mac mini M1, the LG 32UN500-W.

the monitor works great except the whales out color while in HDR mode m, but that’s a know issue.

the most annoying issue it’s that the display randomly flickers and shows lines when the display shows dark tinted colours.

restarted the Mac issue persisted.

changed HDMI Cables, issue persisted.

Fully restored Mac mini in “recovery mode, issue persist.


the issue don’t happen on my 16” ‘Mac book with the same external display as Mac mini,


software glitch? Need to have the Mac mini replaced?


another thing that I’ve noticed is that the same display with the same usb c - display port cable plugged in the 16 k ches MacBook Pro, under the system profiler the external display can get detected correctly and even the serial number is reported, but nothing of this is visible on the Mac mini with the M1

Mac mini, macOS 10.15

Posted on Nov 28, 2020 3:42 PM

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Question marked as Best reply

Posted on Apr 29, 2021 3:18 AM

Just wanted to add my experience with this problem here.


I have a Dell S3221QS 4k/32 inch monitor and an M1 Mac Mini and have been getting this same problem in varying degrees depending on settings - vertical lines appearing in darker areas, which is exacerbated by moving dark areas such as a dark background in a video, or scrolling a website with a black area etc. My own findings have been:


Things that has no effect:

    • The connection method - HDMI, USB-C to DP or USB-C to HDMI - flickering happens with them all
    • Quality of cable - have tried a variety of cables and USB-C adapters, they all have the issue
    • Big Sur version - i'm not sure what the M1 Mac came with when I bought it, but i've kept it up to date and had the flickering on all versions, including on the recent 11.3
    • Display scaling settings - no difference between them


Things that reduce the flickering but don't eliminate it completely:

    • Accessibility options -> Display -> Display contrast - increasing this reduces how often the flickering happens
    • Monitor colour profile - changing this from Dell S3221QS to sRGB had a drastic reduction in flickering, but it hasn't solved it completely.


Oddly enough though, my Macbook Pro 15" 2015 also exhibits the exact same flickering problem on this monitor over HDMI which leads me to think this is a software problem in conjuction with certain monitors, and not an M1 specific problem.


The monitor itself is absolutely fine when using it with Windows 10, I've tried my best to replicate the same colour scheme and conditions but I just cannot get the problem to occur on Windows, so the monitor is unlikely to be the problem here.


I also have a Dell U3415W Ultrawide monitor, and I do not get any flickering with this monitor at all.

Hopefully this can be resolved at some point as it's rather offputting, especially full screen videos and games where the problem is extremely noticable.



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273 replies

Feb 11, 2021 12:14 PM in response to cchhrriiss11

i also had the same issue from the usb c to DisplayPort


try adjusting the sharpness settings on the monitor within picture on the menu , increase or decrease as crazy as it sounds , no flicker so far since doing that.


and agree , it’s disgusting they are ignoring the issue . I think it’s because it’s hardware related and no software update will fix it

Feb 11, 2021 2:30 PM in response to Shane Gosling

something else I noticed in about this on system report . Does this mean the Mac mini is pushing 5k to the display and the display is downscaling it to 4k? Surely there should be a true 4K option for 27" monitors?



BenQ EL2870U:


  Resolution: 5120x2880 (5K/UHD+ - Ultra High Definition Plus)


  UI Looks like: 2560 x 1440 @ 60.00Hz


  Main Display: Yes


  Mirror: Off


  Online: Yes


  Rotation: Supported


  Automatically Adjust Brightness: Yes

Feb 11, 2021 6:55 PM in response to Shane Gosling

I have not had any issues with flickering since switching my monitor to LG 27UL550-W, the only issue I am getting now is that when I wake up my computer from sleep, the scale changes to some awkward stretch which only shows a quarter of the screen on the entire monitor.


For those with the flickering issue, I was considering getting the USB 4.0 hub by OWC to see if this would have solved the flickering issues. Has anyone tried those thunderbolt hubs?

Feb 12, 2021 10:03 AM in response to lwc27

Thanks I have ordered a LG 27UL550 today, it arrives Monday , I assume the -W on the end means white back I couldn't find a LG 27UL550-W only a LG 27UL550 ? lets see if it solves the problem. What worries me is others who also have the LG27ULxxx brand also report some issues so it sounds like specific models work and other do not.


From messing around with the BENQ while working its almost as if its some kind of sync conflict between the image processing the monitor is doing itself and the signal its getting from the Mac mini.


If you think about it , apples own internal LG panels within the iMac and MacBook do not have any 3rd party image processing going on by the monitor chipset. On a given image that makes the monitor flicker if I move that sharpness control the image goes perfect. It then flickers on other images, doing the same brings back the image as perfect again. Sharpness is manipulating the image via the monitors own processing. Shame there is no direct bypass mode where the Mac mini directly controls the panel with no additional processing e.f 'eyecare' , brightness, contrast, HDR etc etc



Feb 13, 2021 11:55 AM in response to Shane Gosling

LG 27UL550 arrived today, I have them both connected to the M1 the BenQ EL2870U on HDMI and the LG on USB to Displayport , I have also reversed the connections and have seen the Ben Q shimmer and flicker / lines while the LG 27UL550 is stable both displaying the same screen. I have also run the expert mode calibration on both monitors (hold down alt when clicking on calibration) and the 2 monitors now look very very similar VA vs IPS.


The BenQ has a bit more punch on brightness and the LG has a more natural colour to it. The BenQ was £250 (although I have seen them as low as £199 last year) and the LG 27UL550 £280 so for anyone needing to get on with it before apple finally finds a fix for the M1 as others and lwc27 have recommended above the LG 27UL550 is perfect.


The only issue that remains now is every time the Mac goes to sleep all monitor settings are forgotten, since the m1 draws hardly any power anyway I think I will just stop it sleeping until apple fixes that.

Feb 18, 2021 4:31 PM in response to cchhrriiss11

Finally found your response, I got exactly the same monitor and I replaced monitor and cable a few times, finally I know this is issue with macbook, I am okay, because I bought the monitor for my ps5, there isn't a good replacement for this monitor, since I am looking for a 32 inch curved 4k display, looks like only this monitor matches my needs, now just hope apple fix this issue.

Feb 24, 2021 5:03 PM in response to crospa91

Same issue with Mac Mini M1 going into 4k Dell P2715Q. Monitor works flawlessly with every other machine; mostly a MBP - it’s a great, reliable workhorse. With the Mini, connected via HDMI, it’s fine, it’s fine, it’s fine... and then loses it, display constantly flickering and going back. Was going to try with USB-C to DisplayPort cable until I read the comments here and thought I’d save myself the effort and cash. This is obviously a problem with all of the M1 units. To say I’m unimpressed is an understatement; personally, I would put ensuring that a computer drives a monitor reliably towards the top of the checklist before daring to release it to paying customers.

Mar 1, 2021 5:15 AM in response to crospa91

I have the issue connecting my Mac mini M1 with the LG 24MK600M monitor.


I have updated latest version of Big Sur 11.2.2


Some websites are flickering in certain colors. I then found some clips to easily test.

https://www.youtube.com/watch?v=tPdLZ9g0l28

https://www.youtube.com/watch?v=LT-oNf3A7IU


Followings are my test result:


If I connect with the new LG 24MK600M monitor using HDMI port, and then I open the clip, https://www.youtube.com/watch?v=tPdLZ9g0l28


at 0:20, the screen of the clip is a bit flickering.


Also, I open the clip, https://www.youtube.com/watch?v=LT-oNf3A7IU


at 3.08, the screen of the clip is flickering over the green color (and other).


If I connect with my old VGA monitor using the HDMI to VGA converter, then open the same clips, it works fine.


If I connect with my old TV using HDMI port, then open the same clips, it works fine.


if I connect my old Notebook (Windows 7) with the LG 24MK600M monitor using HDMI, it works fine.


I try the Calibrate of the Display settings of the Mac, it does not help.


I try to set all modes of the monitor, it does not help.


Does anyone have any solution for this? Thanks.

Mar 1, 2021 10:56 AM in response to LamoonMan

So, is Apple going to FIX this?


It's obvious this is affecting a very large amount of users with many different *NEW* monitors. It seems ridiculous to me that the Mac Mini M1 can only work properly with a small select few monitors. I've been experiencing this issue with my Samsung U32R59x displays (HDMI and DP) and I know there's many other people out there using these same monitors with the M1-based machines and experiencing the same symptoms.


Anyone else getting really frustrated with this issue?

Mar 1, 2021 11:18 AM in response to MacColes

This is unforgivable. My brand new M1 Mac Mini is borderline unusable in my office setup due to this issue. It's been a long time since "it just works" could be relied upon as why we pay for Apple gear (not entirely their fault in a world of malware and security issues) but this is a failure of the most basic functionality. Apple knows, of course, who has bought and registered machines with this fault so it's not exactly great customer service that they have chosen not to acknowledge the problem with the affected customers and give notice of progress towards a solution.

Mar 2, 2021 8:41 PM in response to crospa91

Update: I went to the shop I bought the LG monitor. They tried my Mac mini with new LG monitor with the same model (24MK600M), it had the same problem. They then tried to connect a Notebook with my LG monitor, it did not have problem. So, they mentioned that, contact the shop that I bought the Mac mini M1.


So, I then went to the shop I bought the Mac mini M1. They tried a MacBook Air M1 (because they did not have any Mac mini M1 for demo) with my LG monitor, it had the same problem. So, they mentioned that, they will report the problem to Apple.


I then went to my friend office to try his Mac mini M1 with my LG monitor, it had the same problem. But my Mac mini M1 did not have problem with his Acer monitor.


Mar 2, 2021 10:17 PM in response to LamoonMan

I have the same issue with my new Mac Mini M1 bought last week. I also connected a 32“ 4k Samsung screen. The only situation where I see the issue massively is when displaying music.amazon.de (Yes I have to use that instead of Apple Music, because the Apple Music Skill for my Amazon Echos is useless) website. No issue if I display dark pictures or content. It‘s only happening when displaying this darf website except one other situation. If selected some darker background images, I can also see fine vertical lines on the logon screen. But no flickering there. This is really frustrating, not because I‘m having the issue often, more because I don‘t here anything from Apple (already discussed that with the support) and I don‘t know at the end if it‘s a solvable SW issue or a HW topic.


Today I‘m getting a Thunderbolt to DP cable and my hope is, that the behavior is different instead to the HDMI connection today. But I‘ll see...

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

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