My save was corrupted too. It's quite complicated so this is what happened.
I had just got finished beating the campaign, and had just started up co-op online. I had my RIG upgrades and guns, until asked to switch to disc 1 from disc 2 before starting an online game on prologue. Anyway I started without my guns and the RIG was back to standard, so I quit and checked my save file. Keep in mind I hadn't quit at any point until after I switched discs to find my saved guns missing.
And my completed percent went from 84.6% to 2% and couldn't be more disappointed. I lost all progress and unlocks, can't resume or select another chapter, its totally screwed. My play time is still 15:58:17 which I think the 15 is hours? I'm not sure but need a solution A.S.A.P.As a guy who goes through the game OCD style and picks up EVERYTHING I don't plan on doing it again.
I've checked all internet threads and anything related to this sort of problem but can't get a hold of anything helpful.