Okay so this has been really annoying for the past 2 weeks. I have tried EVERYTHING i could to fix this problem. I've verified the game cache, re installed the game, deleted certain files that it said that would work if i did, and everything else. I am getting really annoyed at this. I messaged steam support and i did what they said and it did not work. So since i cant play i decided to play portal 2 and found out that it gives me the same exact message when i try to play it. I have no idea if its just my source games cause TF2 and dota 2 work fine, but not lfd2 and portal 2. I don't know if installing any games affects it because i noticed after i installed Mount and blade: warband, lfd2 started giving me that message. I installed MAB two weeks ago and lfd2 was working perfectly fine up until that point. Please, someone help i really want to play lfd2 again.