That absolutely solved the issue! Verifying the files' integrity turned up 3 files out of sync. I deleted the .dat file, restarted the game and it worked just fine. I'm a steam light-weight so I couldn't find a way to force it to sync myself. I guess this is not a bug, but a simple fix in any case ...

After a week of play I get a crash on every startup. Problem arose after going from "offline mode" to "online mode". I have to share an account so while the online account was in use, I went offline where I played for several days. When I went back online, steam informed me that my files were out of ...