This is what I get for being careful. A storm came up, I hit save and during my save, the power went out. I'd have been better off not saving at all. I would have lost only half a day.
At any rate, that's what happened. During a save, the power went out. Upon re-entering the game, the game/family I was playing was no longer accessible. The main screen says it cannot launch the game, it may have been saved with data from an expansion pack that's no longer installed. I have all the EPs and SPs, and they're all still installed. I tried moving the actual game and renaming the back-up, but that gives me the same message. Is all lost?