Can confirm this can happen with the new M1Pro 14'' (base model) as well. Connected to a HP 27f 4k display via HDMI, I have the same weird ghosting and flickering after a while. Happened several times with a new Anker USB C hub with HDMI 4k60, but only once with the built in HDMI output. Thought it was the cable at first and then the monitor but came to the same conclusion as everyone else. Tried with a new thunderbolt to DP cable and haven't had the issue so far - will report if it happens again.
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M1/M2 flickering, ghosting with external display [Merged]
- Thread starter aednichols
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Exactly what kind of flicker you are experiencing? I suspect your monitor is in YPbPr mode instead of RGB. Check this thread for more information and examples what you could try if that is causing the problem you are seeing. https://forums.macrumors.com/thread...b.2276345/page-28?post=30553761#post-30553761
So far I have not noticed any flickering after updating to Monterey. Before updating the flickering triggered almost instantly by visiting a specific website I use for work.
No flickering here either, but now my HDMI/USB/ETH dongle doesn't wake up about half the time when the Air wakes up. One step forward, 2 steps back...
Hm, weird - nothing I have noticed. I did have some issues with the USB ports in my Dell screen before updating though, that sometimes they didn't work. So I just had to replug the USB-C cable and they started to work again. So far I have not noticed this in Monterey either.
Just a quick note to say that I'm having the ghosting/flickering problem on my 14" M1 Max MBP running the latest macOS Monterey 12.0.1, hooked up via HDMI to my Dell S2721QS monitor.
It seems to happen randomly twice a week or so, and nothing specific triggers it. I've found that doing a factory reset on the monitor helps -- it doesn't resolve the problem right away, but the flickering lessens and eventually goes away after 5 minutes or so.
It seems to happen randomly twice a week or so, and nothing specific triggers it. I've found that doing a factory reset on the monitor helps -- it doesn't resolve the problem right away, but the flickering lessens and eventually goes away after 5 minutes or so.
tldr; I may have found the cause to this issue, and found a way to fix it. It involves turning off the internal display 'True Tone' and/or 'Automatically adjust brightness'.
I'm using the 14" MBP with M1 Pro on a brand new Dell U2720Q and experienced this problem less than a month into it. I was previously using the M1 Mac mini and never had this issue.
I connect the MBP to the Dell via a Plugable Thunderbolt cable. I also tried changing to HDMI. The flickering and ghosting persists. I don't use the internal display most of the time, so it's set to mirror my Dell and I turned down the brightness.
I called up Dell. The staff asked me to unplug all devices and go into some diagnostic modes which show full grey/red/green/blue/black/white screens. I observed flickering on the grey screens only.
Dell replaced my monitor after getting a video of it in action. It was difficult to shoot it in action, you'd need to shoot in slo-mo to capture the flickering.
Anyway, the problem returned on the replacement monitor, within 2 days I think.
That's when I realised it could be my Mac, and not the monitor. I found this thread. I tried to follow the fix for YPbPr vs RGB on the other thread, but couldn't get it to work. (It remained YPbPr no matter what I did.) I was already on Monterey 12.0.1 when the problem resurfaced, so that clearly didn't fix the problem.
I tried something else, and it's been more than a week and I've not seen the problem return.
What I observed is that before the flickering sets in, my screen would turn really, really yellow. Like, some Night Shift kicking in, even though I did not enable Night Shift. The other thing I started to suspect was that my Mac could be adjusting its color/brightness in response to my ambient environment.
So the M1 Pro MBP internal display has this mode called 'True Tone' and 'Automatically adjust brightness'. Even though it is set to mirror my Dell, I disabled them, and the long story short, the flickering and ghosting problem had not returned for an entire week.
Just wanted to share this here in case it helps anyone.
I'm using the 14" MBP with M1 Pro on a brand new Dell U2720Q and experienced this problem less than a month into it. I was previously using the M1 Mac mini and never had this issue.
I connect the MBP to the Dell via a Plugable Thunderbolt cable. I also tried changing to HDMI. The flickering and ghosting persists. I don't use the internal display most of the time, so it's set to mirror my Dell and I turned down the brightness.
I called up Dell. The staff asked me to unplug all devices and go into some diagnostic modes which show full grey/red/green/blue/black/white screens. I observed flickering on the grey screens only.
Dell replaced my monitor after getting a video of it in action. It was difficult to shoot it in action, you'd need to shoot in slo-mo to capture the flickering.
Anyway, the problem returned on the replacement monitor, within 2 days I think.
That's when I realised it could be my Mac, and not the monitor. I found this thread. I tried to follow the fix for YPbPr vs RGB on the other thread, but couldn't get it to work. (It remained YPbPr no matter what I did.) I was already on Monterey 12.0.1 when the problem resurfaced, so that clearly didn't fix the problem.
I tried something else, and it's been more than a week and I've not seen the problem return.
What I observed is that before the flickering sets in, my screen would turn really, really yellow. Like, some Night Shift kicking in, even though I did not enable Night Shift. The other thing I started to suspect was that my Mac could be adjusting its color/brightness in response to my ambient environment.
So the M1 Pro MBP internal display has this mode called 'True Tone' and 'Automatically adjust brightness'. Even though it is set to mirror my Dell, I disabled them, and the long story short, the flickering and ghosting problem had not returned for an entire week.
Just wanted to share this here in case it helps anyone.
Probably your problems with flickering is because of YPbPr and you did not follow the instructions (in case you tried that in the begin with) how to manually force monitor to RGB mode. Surely with other type of tricks monitors sometimes go to RGB mode but they can and probably will eventually return to YPbPr.
For me, it seems like there is a bug in the OS causing the refresh rate to change when the machine wakes from sleep and it can't be fixed when using HDMI.
I have an LG 34GN850 plugged in to my MBP M1 Pro via DisplayPort. Every time my laptop wakes from sleep, the refresh rate in the display settings changes from 144 to variable. The screen will eventually start flickering when displaying dark colors and eventually I get some ghosting. Sometimes the flickering starts immediately, sometimes it takes a few hours. If I change the refresh rate back to 144 immediately after wake, the problem never occurs. I can reproduce this every single time I wake my Mac. I tried the same with HDMI, but the refresh rate is limited to 85 and 50 hertz. Switching between the two doesn't fix anything.
Resolution is Default for Display on the laptop and external display. True Tone and Automatic Brightness are enabled. The only thing I'm doing to fix it is changing the refresh rate on the external display.
I also tried this on a 13" MBP M1 and it has the same problem.
I have an LG 34GN850 plugged in to my MBP M1 Pro via DisplayPort. Every time my laptop wakes from sleep, the refresh rate in the display settings changes from 144 to variable. The screen will eventually start flickering when displaying dark colors and eventually I get some ghosting. Sometimes the flickering starts immediately, sometimes it takes a few hours. If I change the refresh rate back to 144 immediately after wake, the problem never occurs. I can reproduce this every single time I wake my Mac. I tried the same with HDMI, but the refresh rate is limited to 85 and 50 hertz. Switching between the two doesn't fix anything.
Resolution is Default for Display on the laptop and external display. True Tone and Automatic Brightness are enabled. The only thing I'm doing to fix it is changing the refresh rate on the external display.
I also tried this on a 13" MBP M1 and it has the same problem.
Thank you for the tip, I've now set the Dell external monitor output to RGB and it seems to have worked, at least for now. Hopefully this means my flickering and ghost image problems won't come back. I will post an update if it breaks or happens again.
For anyone else wondering, this is the method I used, in macOS Monterey (apologies if this video has been posted before, I didn't want to search through 11 pages of posts):
Update: well, that didn't take long. A day later, and the same old flickering and ghost image problem has returned. My Dell monitor is still set to RGB, but the same old problem has happened again regardless. The only thing that seems to fix it is to do a full factory reset on the monitor, but even then it takes 5-10 mins for the flickering to gradually fade away. Ugh.
So unfortunately the RGB fix did not solve the underlying problem for me. Very frustrating.
Re-iterating my setup:
14" M1 Max MacBook Pro, running macOS Monterey 12.0.1
Dell S2721QS 4K monitor, connected directly via HDMI
(I mostly run this with the MBP lid closed, so the Dell monitor is the only active display)
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Just want to say that I still haven't experienced any flickering on my M1 MBA using Monterey. So for me it seem to have been solved.
Hey, mind sharing if the problem resolved by itself for you or did you end up using the plist fix to force RGB output? Great that its fixed for you though.
Thanks for the reply. Can I also ask if previously you only had the flickering issue or if you also had the temporary burn in issue and if so, I assume the burn in issue is also fixed?
You're quite welcome. Hm, no burn in that I can remember - only flicker in 5 columns over the screen... pretty weird tbh. It usually hung around for a while too, even when testing to connect to another machine while it was happening.
Are you running macOS Monterey 12.0.1, or a newer (beta) version? I'm on the latest stable (non-beta) release and unfortunately I'm still getting the flickering and ghost imaging. The RGB fix has not worked for me.
Couldn't find a fix either. Returned the Monitor. I still haven't ordered a new one, apparently nothing is safe
I'm not getting flicking but I have vertical lines on the M1 Mac mini. Just tried Belkin HDMI cables from Apple. Same issue. I only have 1080p monitors, but my other PC and 2017 MBA don't show the lines. I think it's the mini. Any ideas?
Just read this news article about a possible fix, an App called " Betterdummy "
www.theregister.com
This is why your external monitor looks awful on an M1 Mac
Q&A with the developer of BetterDummy: from macOS secrets to his motivations
Curious if it would help the vertical dark lines on HDMI? I've already packaged my mini and labelled for return. But I wanted to get an M1 MacBook... would be quite pointless if it does the same thing on an external display too...Just read this news article about a possible fix, an App called " Betterdummy "
This is why your external monitor looks awful on an M1 Mac
Q&A with the developer of BetterDummy: from macOS secrets to his motivations
The better dummy solution does not work for this issue. I've already tried it. I've not used a mac mini, only m1 macbook airs, 2 of them and both of them exhibit flickering and image burn in.