I've been having this problem recently too. Unfortunately it coincides with the addition of a few new mods and a new ENB profile and I've not been able to isolate the cause. The game would crash immediately on saving a game (these are incremented, separate saves using Skyrim Incremental saver). Even though the game crashed at save, the save game is usable, but I suppose probably corrupted. I've now opted for a complete fresh reinstall and new game. Dan, I hope you're right about the free space issue. I'll give the disks a scrub once everything's reinstalled. This is a very frustrating issue and it doesn't seem to be widespread. Could I ask whether others suffering this are using ENB, if so what version and profile? I've been using 1.09 with Sharpshooters Extreme ENB. I don't think the profile is the problem, if anything it might be the new 1.09, but it seems more like a wild scripting issue.