There is a potential fix that has helped some players who have Riva Tuner installed, detailed in this community post: https://steamcommunity.com/app/421170/discussions/0/1630791694323676418/


Also, please try disabling fullscreen optimizations as detailed in this knowledge base article:

https://support.505games.com/en/support/solutions/articles/24000047708


Finally, verify your Steam installation by right-clicking on Indivisible in your Steam Library and select Properties > Local Files > Verify Integrity of Game Files...