I'm having a similar issue. I've been working on four individual SU files. They're all saved locally, in the same folder. Three of them work fine; the fourth, however, has been behaving basically as roland described above. The original file won't save, and it keeps creating backups in numbered sequence. The other three files don't do this, just the fourth.

Anyone have any ideas why this would be happening to one file in particular? It's not much different than the other three. In fact, all four are essentially the same model with just about the same file size.

Thanks for any help!