It is annoying to have to remember to always change this setting back to 1 or else Movie Studio will not render a 4K video. It happened in Movie Studio Platinum 16.0 (all builds), now I just downloaded 17.0 Platinum trial and it did the same thing. Seems like this is a known issue, and why don't they fix it?
This is the error...
This is the setting you have to change to 1 to render 4K