Value cannot be null

[europaJDM]

I get this error popup when trying to change almost any value. How can I troubleshoot it?

[europaJDM]

Changing dithering and refresh rate works, but color depth gives this error. Many other options give this error also.

[Maassoft]

This is indeed a bug when some color setting values are default and return back as 'null' which isn't handled properly. Will be fixed in the next release.
Btw, I think this only happens when "Use default color settings" is used in the Nvidia Control Panel, like this:

If you set "Use NVIDIA color settings" it might be fixed.