What files get backed-up?
Everything which is under the My Documents* folder (including My Pictures*, My Music* and My Videos* folders), or inside sub folders of these four folders. That’s by default, without any user intervention. After Version 1.10.0 the user has the option of selecting what files or folders to backup. If you have a prior version and have important files elsewhere, move the files or folders (by dragging them) so they are under one of these four folders.