Both my BookCouriers sometimes do strange things. I always make a number of folders on each card, and limit the number of files in a folder to no more than ten. Sometimes I get an error message while going through the library saying that a file cannot be played. Tonight I downloaded a new MP3 file into a completely empty folder. When I tried to play it, the Courier started it, and then went back to a file in another folder. It doesn't even give me an error message. Wendy