Closed [UnStable] Won't Launch

I was playing fine yesterday and then there was an update. Now when I attempt to launch a small blank screens appears for a second and then closes--with Steam going through its running/syncing bit. I've tried verifying game cahce, all files are validated, and I've tried launching from directory with administrator privileges. If anyone has any other advice, I'd appreciate it, otherwise I suppose the 22nd is just a week away.

 

I haven't tried it myself, but I noticed that the Unstable Fix mod just updated. Should fix the problem if you don't feel like waiting.