This has happened to me several times now. Each time I've had to delete my current saves and start a new game. It is very consistent. I start having issues when the save file reached 6 MB, then at about 7.5 MB the saves will never load again. This is not a mod issue since it is occurring when I have no mods installed. I have tried a couple of different video cards on my system that has 20 Gig of memory and 3 TB of drive space. I also have the same issue on my son's computer. So it isn't a memory, drive capacity or video problem. I have used the built in utilities to verify and defrag cache files. I have even uninstalled and reinstalled the game a few times. It appears to be a programming glitch with the game itself. This is the first Elder Scrolls gave that I have ever had problems playing, Beth usually does a great job. I hope they come out with a patch to fix this bug soon.