Samsung Odyssey G95NC freezes when macbook in clamshell mode

[MatthewHunt84]

I just purchased better display pro in an attempt to use my M2 Pro Macbook with my Samsung Odyssey G9 57 inch display.
I'd like to be able to use the monitor in a 1440p resolution with my macbook in clamshell mode.

With the macbook open, things work fine with both streaming and mirroring - however as soon as I enter clamshell mode my virtual display freezes. When I try and start a virtual display from clamshell mode my display simply goes blank.

The power is connected, and things work fine when better display is not running.
I've tried a variety of fixes, but nothing has solved this issue so far.

MacOS Tahoe 26.3
BetterDisplay: Version 4.1.5 Build 47757

[waydabber]

Can you try rebooting in clamshell mode and see if virtual screen streaming works then?

[MatthewHunt84]

Can you try rebooting in clamshell mode and see if virtual screen streaming works then?

When rebooting in clamshell mode, macOS starts with the monitor working, but the external display freezes as soon as better display launches.

If I then open the macbook, the mac remains unresponsive on both the built in and external display. Mouse cursor doesn't move, hotkeys to force quit better display don't work, etc.

[waydabber]

Interesting. Honestly, I have no idea why. Can you try turning off mirroring or streaming and just see if the virtual screen works fine in a PIP window? Maybe the configuration is broken somehow. It's very difficult to pinpoint what the issue could be without hands-on with an issue like this. Theoretically mirroring should work just fine.

[MatthewHunt84]

Same thing with picture-in-picture, it works fine until I close my macbook and then the screen + virtual PIP screen freeze until I open the macbook. Maybe I'll try a reinstall?

[MatthewHunt84]

UPDATE: This issue was fixed by switching from HDMI to Displayport 2.1 (I used a USB-C to DisplayPort 2.1 Adapter from CableMatters).

[claude-peon-nyt]

I have the same issue with the same monitor, also Tahoe 26.3 (25D125). I'm currently using DP 1.4. I'm not able to switch to a DP 2.1 cable. I think the last time that I used virtual displays successfully was in January. None of my hardware has changed since then. I'm guessing the update to Tahoe 26.3 broke this feature.

[claude-peon-nyt]

I was able to get virtual displays working again with the clamshell closed by simply resetting my app settings.