Screen flickering after updating to Mac OS Tahoe

I have a similar setup:

Mac Mini M4 Pro with a Dell monitor.

I'd like to share how I fixed the flickering issue.

The flickering is acknowledged by Dell and other vendors like BenQ—even with newer monitors—as something they cannot resolve on their end.

The root cause is Apple's display controller, which applies temporal dithering by default to simulate smoother gradients, even on high-quality monitors. This causes not only discomfort for sensitive users but also severe flickering in some setups, leading to eye strain and usability issues. macOS offers no built-in way to disable it permanently. That would be very nice if Apple would implement this feature.

The solution:

To disable dithering permanently on a Mac Mini M4, you can use a tool like Stillcolor to override the display controller's default behavior and set it to launch at login. Without third-party tools, macOS does not offer a built-in method to persistently disable dithering across reboots.

I have installed the tool with brew. Have a good day.

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I had this issue with an Apple Studio Display connected to a 2021 M1 Pro MacBook Pro via a Thunderbolt cable. This was mainly between switching applications or most severely during conversation switching in Messages. I noticed that this got worse with backgrounds set up for contacts.

To resolve I switched from 2048 x 1152 to the default 2560 x 1440. I imagine since it's using a fixed refresh rate rather than the variable one used at the scaled resolution? There might be a better fix, but that's the easiest one I came up with.

Cheers

Critchlowr wrote:

To resolve I switched from 2048 x 1152 to the default 2560 x 1440.

I imagine since it's using a fixed refresh rate rather than the variable one used at the scaled resolution? There might be a better fix, but that's the easiest one I came up with.

Good computing Critchlowr !

You don't say what monitor, nor how it is connected to your mac. In recent versions, macOS has become quite sensitive to the quality of cables, there are plenty of reports here saying that switching to high quality cable has fixed display issues. This could be the case, or not, of course.

FWIW, I use an 1080p HD Samsung display connected to my MacBook Pro at home, and an older display connected to either the MBP or an a M1 Max Mac Studio at work, and have never experienced screen flickers.

Maybe these only happen in higher resolution displays (for which high quality cabling seems to be a must)?

I have MBP 2019. I changed Display refresh rate from 60Hz to 59.94Hz. Flickering has stopped.

so glad I'm not the only one. Before updating to Tahoe, I never had an issue once. Im on the M4 MacBook Air. Since I've updated, my display started doing this flickering or as I call it, "Blinking" as if it's trying to auto adjust the brightness. Turned off True Tone, auto brightness, etc. Nothing works, and this came from apple support. I think it's a bug and it's getting really annoying to look at.

I have this issue with an M1 MacBook Pro and Studio Display. I tried section77's solution, which is to install and use Stillcolor, and that worked. If you have Homebrew installed, you can install it via CLI using this command:

brew install --cask stillcolor

It installs it in the Applications folder. When you run it, it appears in the menu, and these settings fixed it for me.

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Same here. My company issued MBP M4 Pro, my personal Mac Mini M2 and M4 all have the flickering issue (USB-C connection to external monitor) after upgraded to Tahoe. HDMI works fine.

Hope Apple can address this issue soon.

It's not limited to external display, flickers on laptop display, too. After reading this entire topic and doing extensive research online, my best bet is Tahoe display driver cannot properly handle fast screen changes, i.e. video, window move, etc. I have a M1 MBA before I bought my M4 3 months ago, the M1 was not bugraded to Tahoe and is fine. M4 is bugraded from Tahoe 26.1 and then bugraded to 26.2 due to flickering, and still flickers, no external display involved.

This kind of bugs is not easy to reproduce, doesn't always happen. I used to be a driver / kernel developer, would be nice if Tahoe was able to spit out some error log instead of pretending no biggie.

vbcbb wrote:

After updating to Mac OS Tahoe sometimes I get a slight flickering for 1-2 minutes. I use an Macbook Air M3 and I am connected to an external monitor using a Type C - Display Port cable. Before the update I didn't have any of these problems.

Did someone had this problem?

unplug all non-essential peripherals when testing.

If no issue on the internal display, I would think about the cable or Monitor as the issue and go from there

Got it! Pressing Command-backtick (⌘-`) in Brave to switch windows triggers flickering, not every time but it has happened too many times to be ignored. When flickering starts, other apps flicker as well, but not all.

plotnick wrote:

What am I now suppose to do with my display that keeps flickering at the bottom and nothing I tried fixing it?

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We can't help without details.

What mac, what OS version, what display, how is it connected...

Also: does this happen all the time, or on specific applications?

Does it also occur if you start your Mac in Safe Mode?

Been happening since Tahoe, I notice everytime I use the Message app with dark background and switch to Finder light background or play youtube video.

It feels like low fps flickers or auto brightness auto adjust in non-smooth way.

Apple Studio Display + MacBook Pro M1 Pro in clamshell.

similar problem here since updating to Tahoe 26.1. 14" Macbook Pro M2 MAX (32 core GPU) - Studio Display and two LG DCI 4K displays all directly connected to their own USB-C/Thunderbolt 4 port on the MacBook. The occasional flickering problem is apparent only on the Studio Display, I have not noticed any flickering on the LG displays. The Studio Display is configured as the main display. Like other reports - it's as if the brightness of the white background within in a window is being rapidly adjusted for about one second and then it stops. It seems to happen at random, several times a day.

After updating one of my Mini M2's to Tahoe, the screen flickers constantly. None of the work arounds work, such as stillcolor or changing profiles or resolutions. The flicker goes away if I put the monitor in AV, rather than PC mode. In AV mode, the entire desktop is not visible. Upgrading to Tahoe has practically bricked my Mini M2.

This issue does NOT affect my second M2 that I have connected to an actual TV. I have not connected this Mini M2 to PC monitor to do Apple's testing for them.

A similar thing happens on my M1 Studio after updating ot Tahoe, but instead of flickering, the screen turns to static for few seconds before being restored to normal.

Has not affected my iOS devices that I can tell.