I just went to check the pdf file for a piece I was listening to. Just the other day, I moved all of my pdfs to a single folder, and divided them nicely by composer. When I went to check for the pdfs, they were gone! Somehow or another, they've disappeared! There were over a thousand scores in that folder, some of them quite rare (meaning, I'll probably never find them again). This is severely frustrating. However, I post this for your benefit. If you have a substantial collection of piano related files, make sure you back them up. I still have no clue what happened, but don't let it happen to yourself.