How do I resolve dual monitor issues with Apple Studio Displays on Mac Pro after macOS Sequoia update?

Question

How do I resolve dual monitor issues with Apple Studio Displays on Mac Pro after macOS Sequoia update?

I have been running Monterey happily for years but had to upgrade recently to run specific software. I moved to Sonoma (which had SO MANY problems) but notably, dual monitor support stopped working properly. I experienced one of the following on each restart:

– Only one monitor 'wakes' on startup and all icons and windows are shoved on to that display, necessitating moving everything again once dual monitors are working. The monitor that wakes was randomly one or the other. Unplugging and re-plugging one of the monitors sometimes made both work, other times a restart was required.

– Only one monitor 'wakes' on startup but the computer clearly knew the second monitor was there as icons and windows are not re-distributed and the mouse pointer could move to the second un-illuminated screen. Unplugging and re-plugging one of the monitors would make both come alive.

Due to this and lots of network and file system problems with Sonoma, I have now 'upgraded' to Sequoia.

While the network and file system problems appear to have been fixed (but it is still early days), dual monitor support continues to be broken. Every startup or restart has the second problem listed above.

I have reset power management, nv-ram, unplugged everything and waited 5 mins then plugged everything back in one at a time and also all together.

Does anyone have any ideas how to problem solve or fix this (aside from leaving the Mac on 24/7 which I do not want to do), or do we just have to wait in the hope that Apple fixes this?

For crying out loud Apple, I am running an APPLE Mac Pro with 2x APPLE Studio Displays. This should just work. Dual monitors have been working perfectly for me since System 8 in 1997. Why has this been broken!

I feel like we REALLY need another Snow Leopard moment here. I don't want any new bells and whistles in my production environment. What I really need is an OS that works.

[Re-Titled by Moderator]

Mac Pro, macOS 15.3

Posted on Mar 25, 2025 2:14 AM

Reply

Answer 1

Apr 4, 2025 1:29 AM in response to Tom Grzelinski

Update: This continues to be ridiculous. Every morning upon startup I have to crawl under my desk and unplug one monitor and re-plug it in to make both screens work.

The Mac Pro knows there are two screens attached as it does not re-position windows all on to the one awake screen. Once the unplug/re-plug is done, the one awake screen goes black and then both screens come on with desktop and windows as they should be.

Another side note is that I have my Mail message viewer window permanently on my second screen. This is the screen that always works on startup. However, I also always have the colours palette open (shift-command-C), and this should be on the second monitor next to the message viewer window. However it is being re-positioned onto the main (non-awake) screen at every startup.

If nobody here has any experience with these problems, can someone from Apple support contact me please?

Reply