A few days ago I bought a Sansa Clip +. I tried to add some audio files on my microSDHC card. Although the files have transferred successfully, but some files disappear, and memory card space is still occupied.
You’ve got to edit your file names and also the ID3 tags and get rid of all those Asian characters, slashes, dots and maybe some of those brackets and parentheses too.
The files are there; it’s just that your Clip+ can’t read them in this state. The ID3 tag (which is the info that your Clip sees and displays) has to be in a Latin-based character set or format, specifically ID3v2.3 ISO-8859-1.