Sansa Clip+ not syncing some songs

For some reason, when I sync my Clip+ there are some songs that don’t get transfered to it. What causes this and how do I fix it?

Thanks.

Without more to go on, we couldn’t even begin to guess.

I have a playlist in Windows Media Player and when I sync the songs, 120 of 190 sync fine. The remaining 70 don’t. They are all MP3s. What other info would help?

Do any of the songs in the playlist have international symbols?

(I have that problem when I sync playlists to any device in a program that isn’t WiMP…I use Media Go and get an error of an item or items getting omitted from the playlist after syncing because of the limit of international symbols being exceeded.)