While mirroring screen goes pink/purple when file dialog is open - known Sonoma 14.7 bug, fixed in Sequoia

[Sratarak]

For example when you open any app for instance Microsoft Word, and you go to open a Document, when the Finder window opens, the entire screen goes pink/purple.
When exiting the finder window this goes away.
This only happens when streaming from a Virtual Display to the main Display.

[waydabber]

Not sure why this is, could not reproduce so far. Is this a streaming or mirroring problem? The issue title and description does not seem to match.

[Sratarak]

So I have a Virtual Display with Mirroring Virtual Screen enabled to my actual display so I can access higher Resolutions then natively offered.
While this is turned on, when I try and open a document in an Application, i.e. hitting cmd + o and it pops up the finder window to browse, it turns the whole screen pink/purple. I've attached a photo to show this. This does not happen when not mirroring a virtual screen, and happens on 3 separate monitors.
I've confirmed BetterDisplay has Accessibility access and all the other access required, and performed multiple reboots.

[waydabber]

Hmm. This does not seem to be very usable indeed. But I have no idea why this happens, never heard about such a thing. :) Do you experience the same if you use streaming or simply looking at the virtual screen in a PIP window?

[kusokpnz]

hi, I have exactly the same problem, specifically with finder when opening its window: open > / save as >
Without mirroring mode there is no problem. In mirroring mode at any resolution:
black or purple screen and the mouse cursor is visible. Esc - apparently closes the finder window (open\save) and returns the normal screen.
I came here looking for similar problems. Initially I thought I had problems with my high screen resolutions.

BD 3.4.1

[kusokpnz]

with this black screen, the screenshot remains normal, for example in sublime I executed "file > open" and the screen turned black, at this time I took a screenshot

[waydabber]

Interesting. Again, what config do you guys have? Does it happen with streaming as well? I am not sure what could be done to fix the issue as mirroring is entirely managed by macOS, but it would be educational to see if there is anything common in the affected setups.

[Sratarak]

Doesn’t happen with streaming, only mirroring. I’m on 14.7.x as it’s a corporate mac. Accessibility settings are all standard

[kusokpnz]

Interesting. Again, what config do you guys have? Does it happen with streaming as well? I am not sure what could be done to fix the issue as mirroring is entirely managed by macOS, but it would be educational to see if there is anything common in the affected setups.

BD 3.4.1
MBP (M3 Max), Sonoma 14.7.4
Monitor: 57" Samsung Neo G95NC (hdm<>hdmi).
Internal Screen: Off (laptop always has lid closed)
BetterDisplay+virtual needs for "Enable resolution over 8K (4K HiDPI)"
In mirror display mode the problem occurs in any resolution and hidpi lodpi (and with native resolution)
sysreport:

  Displays:
virtual:
  Resolution:	11520 x 3240
  UI Looks like:	5760 x 1620 @ 60.00Hz
  Main Display:	Yes
  Mirror:	On
  Mirror Status:	Master Mirror
  Online:	Yes
  Rotation:	Supported
Odyssey G95NC:
  Resolution:	11520 x 3240
  UI Looks like:	5760 x 1620 @ 120.00Hz
  Mirror:	On
  Mirror Status:	Hardware Mirror
  Online:	Yes
  Rotation:	Supported
  Television:	Yes

[waydabber]

Hmm. Do you experience the same when you mirror it to the internal display or use different (sub-8K) virtual screen resolution?

[kusokpnz]

interesting testing, probably the problem is actually in MacOS

I connected 27 2k instead of 57 monitor (hdmi <> hdmi) (with change hdmi cable, for testing)

Virtual main > mirror > 27 monitor:
I repeat opening through finder, I get a purple screen

Off virtual screen (BetterDisplay), opened the laptop lid:
Internal display main > mirror > 27 monitor:
I repeat opening through finder, I get a purple screen (but internal display is normal and show finder)

We can conclude that the virtual display has absolutely nothing to do with it
(the only thing I haven't checked is that I haven't tried to completely quit the betterdisplay during the test with the built-in display)

[kusokpnz]

This is a sonoma bug. updated to sequoia 15.3.1 (from Sonoma 14.7.4) , the problem went away in all variations

(fyi: https://www.reddit.com/r/MacOS/comments/1ic4ysl/pink_screen_on_mirrored_mode_but_only_when_dialog/)

@Sratarak Try update to sequoia

@waydabber, Thanks for the tips and the betterdisplay app. I think the issue can be closed.

[waydabber]

Thanks @kusokpnz for the tests and the info!

[bnorconk]

Wondering if anyone found a solution to this issue besides updating to Sequoia (macos 15). Upgrading is not an option for our computer labs due to software requirements.