So I went to play l4d2 5 minutes ago and the button said install. I was confused so I went to the drive where the data was and found it was all there. I launched it from the application directly and when the game loaded, I got a message that said "startup option is set to -insecure, cannot access steam servers." I was already logged into steam, every other game worked just fine. Even wierder, i restarted steam and the problem went away. So what happened? I didn't have to verify the cache or anything, it just went away.