'An unexpected error occured. The file doesn't exist'

This is starting to happen more and more frequently. I have scanned in a document and at the very end when I go to save it, it says 'an unexpected error occured. The file doesn't exist.' It is so frustrating as I then have to scan it all over again. There seems to be no pattern to it, it just happens every so often. I can then scan the same document again and it will save. It's really annoying!