[TopHat]

Forum members: Joel has been really helpful with my corrupt file.

Moral of the story: don't store files on USB sticks or disks formatted in MS-DOS (FAT) as this can cause them to become corrupted. This is true for many different types of Mac files - not just OmniGraffle. Damage can be done to the resource forks etc.

Most USB sticks come in MS-DOS (FAT) format, and although often they will work fine, I would reformat them ASAP in a Mac format.