I have not had a problem with iTunes tags from a Windows version of iTunes–but I won’t update past iTunes 10 because the next versions are so ugly.
My iTunes gives me ID3v2.2 tags, and the Sansa can handle those. But it’s possible newer iTunes make ID3v2.4 tags, which Sansa doesn’t like.
There are also other possibilities. If you are on an Apple computer, iTunes doesn’t just make mp3 files. It makes Finder files that look like ._01-Track 1.mp3 and are 0kb in size. Note that they start with period underscore.They’re usually in folders called MACOSX. They are not songs, but since they have the mp3 file extension–nice work, Apple–they confuse the Sansa. Make sure you haven’t transferred the finder files rather than the songs.
You might also change the bitrate in your iTunes importing settings to 320.
Or, as suggested above, get mp3tag.
http://www.mp3tag.de/en/download.html
Download the file called mp3tagsetup(version number).exe, not anything you might see on a big DOWNLOAD button.
If you are on Mac get KID3, a different free tagging program.
I use mp3tag, so here’s how to use that. When you install it, let it add itself to context menus. Open in, go to Tools/Options/Tags/Mpeg and make the Write option ID3v2.3 ISO-8859-1. Save that.
Right-click an album folder and use mp3tag from the context menu to open it. Make sure the tracks are lined up top to bottom in playing order (you can click the Track header if you need to). Highlight them all and go to Tools/Autonumbering Wizard and choose the Leading Zeroes option. This will number your tracks 01,02, etc. (not 1/11, 2/11 in iTunes style) and will change them to ID3v2.3 ISO-8859-1 since that’s how you set it. Takes seconds per album, makes it Sansa-friendly.
KID3 has similar options that you can find in its help file. The important thing is to save tags as ID3v2.3 ISO-8859-1 (the ISO is Windows alphabet encoding).
