External Monitor Issue After macOS Sequoia 15.1.1 Update

I could be wrong, of course, and I hope to be, but barring any interference, this looks like a hardware problem.

Disconnect any peripherals, and see if there is any change.

You could also try installing an older OS in an external drive, and see if that makes any difference.

Hi again,

Curious thing, with same computer, Macbook Pro 2018 Inter with T2Chip, the issue happens in one external TV, the one described in my previous post but it does NOT happens in another TV with same adapter, very weird.

This means that it does not happen to all monitors, it seems taht HDMI management has changed in some way that some vendors are not ready for?

Regards

I'm back to Sonoma on both the MacBook and the Mini. At least they seem to be supporting two previous OS versions, so I should be fine for a couple of years ... enough time for them to fix this issue?

This is incredible!!

I updated to 15.2 and the issue dissapeared for almost 4 days, and now it happens again.... how is this possible?, I contacted apple and they told me they dont have notifications about similar issue regarding Sequoia....

I will uninstall Sequoia and will try Sonoma.

It's definitely not older hardward only. At least my issue, where it flickers for 2 seconds, is happening on a brand new Dell Ultrasharp I bought late last year, and was running perfectly fine until I updated to Sequoia. It is connected directly to the Mac (also purchased middle of last year, a Mac Studio M2) via USB C for all audio/video, and powered externally.

I just started a new job and was happy to get an Airbook with the M3 chip and an Asus monitor. I had Sonoma and hooked into the monitor with an HDMI to USB adapter, but it made my mouse jittery. I updated to the latest Sequoia 15.2 and bought a new USB-C monitor cable for a direct connection.

Now the monitor just flickers. It turns on, then off, on and off... I did everything here on the thread to fix it. Deleted the preference file, restarted, unplugged, etc.

I haven't yet downgraded back to Sonoma, but that is my next step.

I would blame the cable or something else, but the same thing happened at home when I connected via a USB-C to HDMI adapter. I thought my adapter was just bad and that caused the blinking, but now I know it is something with this Airbook.

I searched for this issue... I can't believe I am the only one who has it.

I hope there is some fix. It is so frustrating. I have wasted an hour already today.

There is no doubt that this problem has a serious impact on those affected. But, since it does not affect everyone and, in fact, it seems to affect only a minority of users, it seems futile to expect that a software update will fix it. Instead, you should try the solutions offered, particularly the deletion of windowmanager preferences.

Unfortunately, my USB-C to HDMI cable from UNI had been the first one that showed the problem. With every Sequoia update I do try that one, up to now without success. I tried three other hub adapters, only one of them works, but only at 30 Hz ... disappointing.

So, dear Teichfrosch, which adapter do you use now?

My impression is, that the UNI adapter gets warmer than e.g. with Sonoma, but not sure...

I guess if you're lucky, the various fixes proposed here and in other forums will work for you. For me, it seems like totally a bug in the OS: I just got a refurbished Mac mini M1 from 2020 that's been erased and factory reset. It came with Sequoia 15.1.1. I didn't wait and updated straight to 15.4. Within 30 minutes, the "flickering" appeared. Same cable, same monitor that used to work (and still works) on my other Mac mini that's on Sonoma.

I have an M1 MAX MacBook Pro and have used it for several years now with a Setechi usb-c to VGA multipurpose adapter (various usb connections, card reader etc) connected to an AOC monitor. It has worked perfectly until the Sequoia version of macOS. Now often when the computer goes to sleep the monitor wakes up in a very low resolution blurry mode. I have tried all the display setting and nothing fixes it. Unplugging it from the adapter or unplugging the adapter and plugging it back in fixes the problem however. having to constantly plug and unplug the display or USB from the machine is extremely annoying and must be a bug in Sequoia since the exact same hardware worked perfectly for several years before the OS update... Anyone got a solution?

Okay, I'm sharing how I solved my problem.

I have an M1 MacBook Pro with Sequoia + Displaylink Release: 1.12.2 | Apr 28, 2025. My dock is a Dell D6000 updated to the latest firmware + two monitors.

Problem: They randomly shut down until they were completely off. I tried every possible option.

I solved it by downloading the Displaylink driver to version 1.11.0.

Good luck!

Maybe you have one of those docks that require "DisplayLink" software? If that is the case, make sure to update DisplayLink to the latest version.

Anyway to test another monitor or adapter?

TxPomeroy wrote:

How do that on Mac Air M2? I've only had the mac since march. Still learning and system search didn't bring anything up?

Tell us the exact model of your dock, and should be able to determine if it uses DisplayLink

UtechSmart USB C Docking station model UCN 3270-2

Bought back in October of 2021 off Amazon

It worked fine until this morning. Not sure when OS got the update but haven't used the mac in a few days since use Windows laptop for work and that's most of my time.

I updated the DisplayLink driver on my mac from the Synaptics website and restarted but still not fixed. Maybe there is somewhere better to get the driver from?

The cheap little dock on my wife's mac was bought August of this year and works fine on both our macs. So, naturally, I'm highly suspicious of my docking station and have ordered a new one.

BTW, thanks for the help. It's greatly appreciated.

Happy Thanksgiving!