Is it game data or game save? if it's game save you can delete your local game save data (this will not affect multiplayer progress but will erase your campaign progress. if it is your game data delete your game installation data and reinstall your game and all DLC and that will clear up the error.
I recommend to manually delete the save by hitting the "Xbox button" in the center of the controller, scrolling to the right and go into system settings, then local storeage and then games and find the BF3 folder and delete the game save (nothing else). You will lose all of your campaign progress but your multiplayer stats, rank, and unlocks will not be affected since they are stored on DICE's servers. After doing this the next time you start BF3 it will work as it should.
COOP is multiplayer so your progress completing them is recorded by DICE's server. Try to load the campaign, if you can't you've already lost your campaign so it won't matter deleting the save since it is corrupted and unusable. If you've already completed the campaign you've also nothing to lose since you have the achievements already.
