I have a weird situation. Windows 10 PC with portable aegisub version r8942-portable-32. I also have Avisynth+ installed if that matters. This one version on this one system can open some of my 4k videos. On my new Windows 11 system I can not find a single instance even with AVISynth+ installed (if relevant) that will open the mkv videos. Complains about colorspace issues. However the version on Windows 10 launches that same video fine. I set this up a while ago and can't remember what I did to get it working. Any thoughts?

Should note on the working one Video provider is set to FFmpegSource but trying both on the Windows 11 system no joy.

JR