Trouble with Saving?

Has anyone had any problems saving Jet reports.
I regularly make changes to the format of reports, (In design mode) then save them, and all seems to be fine, then the next month when I go in to the same report I find that my changes hadn't saved.
Its very sporadic, it doesnt happen all the time, and on various different reports, unfortunately, because I dont jot down, every single change I make, it makes it very difficult to log when it goes wrong, and I just have to duplicate my work over and over again until it decides to keep the changes.

Has anyone else had this problem, if so have you managed to get a fix for it?

Taryn