In the past I had embedded (id3) tags like album art for example (I used it for chord charts), and the MP3 player on MS refused to play those.
Interesting, yeah that could be it. Must do some tests here to verify that.
This problem doesn't directly effect me at all, but Liosntracs lost a sale because of it. My brother-in-law is a signed DJ and I finally get him into the studio to see the Mediastation and it lets me down. It wouldn't play many of the mp3's he had on his portable HDD.
Put him off the idea of buying it totally. Even if a fix is issued, it would be very hard now to get him to look at it again as it not playing a song is a DJ's worst nightmare.