Thank you Black-Rectangle. When I attach my Sansa to my computer, there is a path Computer\Sansa Clip+ 4GB\Internal Memory\Audiobooks shown in Windows Explorer. The subfolders I am talking about are the next step down from this path. When I play the Clip, I go to Music –> Audiobooks and then to the book in question. The books are there on the Sansa display, usually with a name I can recognize, but sometimes several books are there bunched into a single designation “Unknown”. I never use Folders under Music. So my question is, I guess, is: How to I enter a useful name tag for a book using Mp3tag or Windows Explorer or whatever?. As I mentioned before, when using MP3tag to try to point to the subfolder of Audiobooks, I get an error message.