Unable to change white viewport background

[info]

So when I opened up 3ds Max today the viewport background was completely white (with black grid) and I'm completely unable to change it. If I open up the Color panel in Customize User Interface the viewport color is set to the standard grey even though the background is white. I can change to whatever color I like in the panel but the viewport color will remain white no matter what I set it to. I can continue to work on my file without issues but the white color is definitely annoying.

[info · Accepted solution]

Solved: the viewport background was set to Environment Background instead of Solid Color.

[CAMedeck]

I'm glad you found the solution so quickly.  That was exactly what I suspected as I read your first post, mostly because I have run into this myself.  Shaded views tend to default to showing the Environment Background.