Ok, so a LONG time ago back in like early 2011, I bought The Sacrifice and The Passing DLC for Left 4 Dead 2 and I also downloaded a modded User Settings around that same time. Loaded the game, popped up on the main menu and it said Corrupt save for both DLC's. I have a different UserSettings now, but I still can't load my DLC. I was wondering if anyone specialized in fixing saves like that? I can send the original DLC files I have if anyone would want to take a look into it... :|
same thing i was going to suggest. if the dlc is corrupt usually means didn't get downloaded correctly.
wellhas long has u payed 4 the DLC, den delete everything to do with L4D2 and redownload it, if that still dont work den call M$ Support and tell them yr DLC is not working and u have payed 4 it but dont tell that ure going to mod it. lol they should b able to help u more if none of XPG can help.
Are you playing offline with the cache cleared or offline in general? If so, it won't work because the DLC has to be "connected" to the internet in order to work. Same happened to me numerous times.