Bug/Issue Unstable - Says "Running", "Syncing" then doesn't launch

Like it says above, when I try to start the game in Steam it says "running" then "syncing" by the game in the sidebar, but the game doesn't start and there's not even anything showing up in the task manager.

I've deleted the local data in Steam then reinstalled, done it in Steam AND manually checked then reinstalled, and double checked my drivers. Still can't figure out why it's doing this and it doesn't give any errors or anything to give me a hint.

(All my other games, including stable, are working fine, by the way.)