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

Display flickers Solved

If you are using HDMI cable, You have to change this option to solve this problem. Click>system preferences>Display>Refresh rate> set to 60 Hertz. Check screenshot plz.

So far this is the list of monitors reported with flickering Issues.

LG 32UN500 

Dell P27S21Q 

LG 27UL600-W Phillips PHL288B6

PHILIPS 328E

Dell S3221QS

LG 27GL650F-B 

ASUS MG28U 4K 

DELL U2421HE

DELL U2421HE.

Samsung U32R59

Dell S2817Q 

Dell U2718Q

LG 32UN650 4K

Dell U3818DW

Dell P2715Q. 

LG 24MK600M

Samsung LU28E590DS/ZA 28" 

Samsung R32R59x 

HP Pavilion 23xw 

LG 24MK600M

BenQ PD2700U

LG 29UB67

AOC 2879VF

PHILIPS 328E 

4k 32UL950-W.

LG 27GL650F-B

MSI MAG321CURV 4k

LG 24MP59G-P

Samsung LF24T350FHLXZX

ASUS PA248QV,

BenQ PD2700U

BenQ EL2870U

AOC Q2963P

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.

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.

Just to be sure I have the same issue, is yours the same as the video ive posted below? as I was considering returning the monitor as I thought the problem was with that.

I ran the Mac mini through my LG 4k OLED tv and its perfect.

my monitor here is the LG 32UN500-w

im not sure what else to do. should I just keep the monitor?

https://youtu.be/_lCJf3tGdHw

I have a call scheduled for later today. I’ll let you know what apple support says. In any case, LG says it’s up to apple. And if you google OP post about it, you’ll find he returned the monitor and went for Benq :)

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...

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?

So I've spoken to Apple support. A nice conversation, but not helpful in the end. They asked if contacted LG, told me to restart my Mac etc. They suggested that I try to connect via USB-C. After ruling out the obvious they said that they will notify people up the ladder. Apart from bugging them like this (via support) it might be useful to let them know via https://www.apple.com/feedback/macmini.html

I think I will be forced to return my monitor and try another model/brand.

Got the same issue with BenQ (see my post and report here: https://discussions.apple.com/thread/252831568). My local AASP diagnosed it and it needs main logic board replacement! Woohooo! I've only used the mac mini M1 for barely a month.

I sold my S3221QS to my brother (he uses a Windows device) and bought a BenQ EW3270U and I've been flicker-free so far.

Dell did admit to me in an e-mail that the S3221QS isn't compatible with the M1 Mini, which leads me to believe it's more of a manufacturer issue. Still frustrating though.

From an e-mail received by Dell (I didn't buy one of the parts to try their fix, as I don't think there's a guarantee that fixes it and didn't want to dump more money into the monitor):

Upon further checking with our support specialists, the issue is confirmed to be a compatibility issue and the only resolution provided is to use any of the following adapters

• Dell USB-C to HDMI Adapter (Dell Part #47KD7)
• Dell USB-C Mobile Adapter - DA310 (Dell Part #0XJD9N)

Hi there. This problem also occurs on my AOC c24g1 monitor. When displaying dark colours the monitor flickers with grey diagonal lines. This also happens in Logic Pro X with its dark grey UI..

Using Mac mini m1

Hi All,

I have two Benq 4k monitors connected. One by display port and one by hdmi. I used to get shimmering and flickering and random lines etc etc as many of you are experiencing. I appear to be one of the lucky ones that have completely eliminated the issue. See the settings on the attached screenshot. To be clear - these settings work on my duel benq el2870u 4k displays. Hope this helps some of you. Key to the fix is enabling HDR. If I switch it off, the flickering comes back. Oh yes, just remembered. I have also disabled night-shift!!

Yeahhh, no luck.

The last conversation I had with apple techs we tried wiping cashes in the two libraries listed in the photo below and rebooting for a moment everything was working great!! tho, a few moments later the caches refilled and the color flickering started again. If someone knows more about the inner workings of the libraries, there might be something worth exploring.

I Ended up caving and cashing in on my BestBuy protection plan. Traded in for a Samsung UR55 that (so far) has been perfect! highly recomended if youre looking for a color accurate 4k ips, not too pricy either.

Same monitor (LG 32UN500-W), same Mac mini M1. Tested two different cables (glitches persists). Big Sur sometimes reports the monitor as 5k (?). Also tested the same monitor + same cable + MacBook 15 (mid-2014) = everything ok. Same Mac mini M1 + same cable + LG TV 4k HDR (MY 2019) = everything ok. So it's not a monitor, cable problem. It's a Mac mini M1 + Big Sur problem. Looking forward to Apple producing correct driver soon.

It's present in 11.0.1 and on 11.1 public beta (v. 1) which I am currently on.