I'm afraid we don't have a fix for you at the moment beyond a clean install.
Clean install in case you don't know how to do it:
A clean install means not only deleting the game but also clearing out the folder associated with it in 'my documents>paradox interactive' which might help. Do remember that this will delete ALL your saves though so you may want to back them up first!
I have the same problem where the launcher says a couple of DLCs have corrupted files. Re-installing after deleting all the contents of that folder unfortunately doesn't fix this.
I have Win7 64 bit, the things I've tried:
. verify integrity of files using the Steam software
. Un- and reinstalled game
. Un-check all DLC in Steam, deleting files within mydocuments folder, check all the dlc again to install them
. This one above, but added un- and re-installing the game
I have unsubscribed from all mods just to be sure that wasn't influencing it in any way. However the exact same dlcs throughout all the steps taken show the warning message icon "the files for this dlc appear corrupted", the dlcs in question are:
- Horsemen of the Crescent unit pack
- Conquest of Paradise
- Songs of Yuletude
- Wealth of Nations
- Res Publica
- Republican Music
- Art of War
I can start a game, but I am unable to do things like: sell ships, ask for war reparations, go to war using my vassals claims. Which I am assuming are part of the dlc that are affected.