The Mods show up in my addons and are not conflicted and are ticked but dont work in single or multiplayer campaigns. I tried taking the mods out of the workshop folder but it still didnt work after i puylled them out unsubscribed,deleted the folder. I tried uninstalling and re-instlling but that does not help either. It says that the files are damaged when i try to open them (.VPK) and i tried opening them with Source Finagler. Please help as my friends works fine and he did not have to do anything and he is using the same mods and a mac as well with a steam copy of L4D2 like me.