MacBook Pro M1 Pro issue with dual display after updating to macOS Sequoia 15.1

I was having this issue running 3 external 4K monitors through an "iVANKY FusionDock Max 1" dock and routed through an HDMI KVM. At first, I thought my issues were due to my Thunderbolt to HDMI cables or my KVM setup.

I tried multiple fixes, but ultimately, the problem was only solved after switching to the Apple 1M Thunderbolt 5 pro cables between my dock and my M3 MBP instead of the cables that came with the dock.

Apple definitely needs to develop a software fix, but for those dependent on external monitors, this might be an (expensive) workaround.

I tried other cables, even those marketed as Thunderbolt 4 and 100GB USB-C, and even reverted to MacOS 14.7 for a while; this was the only fix that worked for me while running MacOS 15.1.

First of all, you need an image. This can be downloaded from several websites - Sorry, I am on iPhone here and can’t post the links that you will find them if you really want to

Download the.PKG installer

Then install it and from your applications folder using terminal (there are scripts around, it’s not too hard but it takes a while, I almost aborted due to missing progress…), you can create a USB boot, medium

Be sure to have a time machine back up that was made on 15.0.1 otherwise it won’t work

Then reboot your Mac holding The startup key and boot Into options

Repartition Your hard drive. (completely delete)

After that reboot or select your USB boot medium and install Sequoia 15.0.1

Now you can use your Time Machine back up to restore your Mac. If you don’t have one, you have a Mac on factory settings now

So much for an ultra short info, that worked for me

Same issue here..... MacBook Pro M1, external screen Philips Widescreen....... Really I got a 2nd MacBook for work... but if I had that updated.. I really had a issue. Why does it take so long to fix.....

I have one 'dumb' workaround that all of you could try.

While connecting an iPad via Sidecar, the HDMI display comes to live, but stops working the moment

the iPad is taken offline.

This is not a solution, but at least proof that nothing is wrong with the display, port or cable.

Rather something totally borked with how the display is detected.

Ok, so I have done some massive re-plugging of cables and I may have found something, that can help some of you.

My Setup:

M1 Pro MBP 14" + Anker TB4 Dock + Dell 4k + LG 2k screen (240Hz)

I have removed all HDMI Cables from the setup and I connected the LG Screen via DP to DP Cable to Anker Dock. The Dell Screen is connected with DP to USB-C cable to the dock. Here is the interesting part:

When I connect both displays to the dock and then connect the MacBook, the Dell screen (connected with DP to USB-C to Anker Dock) keeps turning on and off every few seconds. The LG Screen is fine and it shows 144Hz Refresh rate.

When I unplug the dell screen from the Dock and THEN connect MBP to the dock, then the LG Screen shows 240Hz rate and it still works fine. Then I connect Dell screen to the dock and it almost never flickers. Maybe 1-2h per hour. AND the LG Screen works with 240Hz still.

So, connecting the MBP first, then plugging the dell display might alleviate some issues until the update is out.

Hope this helps!

OK, this is basically my set up and I got frustrated and tired of waiting. The Caldigit T2 was on sale on Amazon so I got it and needed an DisplayPort to HDMI adapter… but it works!!! So maybe this is something with USB-C to HDMI or maybe it’s the Anker hub? It sounds like other people had a more direct USB-C to HDMI, so it seems like it’s that. But why would Displayport to HDMI be better? Now it’s perfect again though.

I'm using Macbook Air M2 the monitor I used with usb-c in Sequoia version 15.0.1, when I updated to version 15.1.1, I can no longer use it, I seem to be connected in the displays section, but no image comes. I installed sonoma version 14.7.1 to solve the problem but it did not solve it. For now I can overcome this problem by using hdmi.

I had the same issue with Sequoia 15.1 and found a software update under software updates in system settings that fixes the issue for me. I tried to post it here, but Apple deleted my post to tell everyone the fix (because they don't appear to care about any of their users actually being able to use any of their hardware or software?). If anyone can find a way to update to a newer Sequoia version then this is what worked for me.

2021 M1 Max MacBook 16" 64gb ram 24core gpu.

just started having the same issue last night. The difference though is I haven't updated. I'm still on sonoma because I am an audio engineer and have to wait for a while before any major updates because of audio plugins not being ready yet (it just happened ugghhh!!!)

I initially thought it was a power issue or cables because this has never happened before, but it's doing the exact same thing with three monitors and the display on the actual Mac. I do feel like it's a power issue still, but the issue being the ports because my external ssd loses signal and I get the error notification. That in itself is a. bad thing for the drive.

But again, I haven't updated and am using 14.6.1.

Also, have any of you noticed your system being sluggish as well when this started happening?

So yeah, no update, no new hardware. Everything is the same as it was when it was not a problem. uggghhh

I've been using the same Lenovo 4k display with my Macbook Air M1 over USB-C cable without any problems for 4 years. I upgraded from Sonoma to Sequoia yesterday, and today connected the external display. Immediately started seeing the external display disconnect 1-3 times a minute.

Only thing I changed in a working setup was the macOS version.

"Finally the issue for me is solved. Instead of using a HDMI to USB-C adapter I purchased a DisplayPort 1.4 to USB-C adapter connected to the Dell G3223Q 32" and no more issues. I also deleted the display preferences files in MacOS:

/Library/Preferences/com.apple.windowserver.displays.plist

/Users/<YourUser>/Library/Preferences/byHost/com.apple.windowserver.displays.<ALPHANUMERIC_CODE>.plist

In the last case, it can be multiple files.

And then restart. I hope it can help

(2)"

This worked for me! Thank you.

Macbook Pro M3 with 15.1.1 installed, did what was suggested above, restarted and reset the settings as it was showing me an ungodly horrible view with my 49" Samsung connected via USB-C to Display Port which is the only way to get the 5120x1440 resolution. Once all reset, 240Htz and Clamshell mode operating as it should. Still filing complaint via the Product feedback page.Bug report submitted, thanks for the help Fam.

I have updated to 15.2 and the issue is not resolved. I am using Anker TB4 Docking station. After switching from HDMI to DP Cables, the issue was less present, but it is still there... extremely annoying from Apple :/

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.

Hi again,

I persist with apple to get more support, they told me that really they don't pay attantion to the apple discussions threads, and they don't have a lot of tickets regarding issues with external displays.

After changing cable, adapter, reset SMC, PRAM, restarting and even go back to SONOMA (yes the issue for me is still in SOnoma as I came from BIG SUR) the situation is still the same, connected TV randomly siwtch off for 3 or 4 seconds.

Please guys, open a ticket to apple support in order they have more and more tickets and pay attention to us.

Regards.

Updated to 15.2 today, problem not resolved.

In fact, it's worse now; before my screen went black for a few seconds, now it's 10 seconds or even longer.

The screen now also goes black after a few minutes of inactivity although it's set tot do that after 30 minutes.

A new problem, possibly?

How is Apple informed of this problem? Do they check the community posts or is there a way we can inform them of the issue directly?