Can't play some mp3 tracks on iPod Classic

I see the same problems with about 1/3 of my MP3s. The files play fine on OS X and Linux, they get transferred correctly to the iPod but they don't play on the iPod. The progress bar just sits a 0 seconds forever. When I want to sync the iPod after trying to play one of these files, it freezes and I have to reset it.

I didn't find out what causes the files to not play on the iPod yet. So far I've ruled out lame (encoding the track another time with the same settings produces a playing MP3) and mp3gain tags. The only thing left to check are musicbrainz tag (added with Picard).

I had the same problem with some of my tracks,and I resolved it by converting id3 tag to 1.1 version with itunes.

Erm. . . I have a similer problem, I dont exactly know what kind of ipod i have (original, 5th genreation, touch, video, ect.) but its 30gb and i have all my songs in my library and its own file AND it plays fine when I play it in itunes BUT when i try to sync or drag and drop my songs it says " SONG cannot be played on this ipod because it cannot be played on this ipod" i dont think its the problem but it might be because they are MIDI's. But this error happens to all my songs SO i have no clue about what to do . . . help??

-Person with a Problem

I'm having exactly this problem. While I appreciate re-encoding the problem mp3s seems to fix the issue, I feel rather reluctant to go through this hassle for the 2000-odd mp3s which won't play just because of one device. I have hundreds which won't play I straightforwardly ripped from CDs in WMP - what's wrong with that!?

I'm rather annoyed at Apple. My old iPod played all my mp3s without issue. I have no problems playing them on any other device. So why, with this new, supposedly more sophisticated iPod Classic are these problems cropping up? It seems utterly ridiculous.

Is it crappy software on the device? Is it poor testing? Or is it some petulant move by Apple to somehow standardize formats and only play what "they" deem suitable? Either way I'm a very unhappy customer and would have second thoughts about buying another Apple product. Currently its all marketing not being backed up by delivery. You can have all the Coverflow and touchy-feely features you like, but if you can't do the basic job of playing the music itself then what's the point?

Yeah, I'm a bit annoyed by this too.

The "ENCODED WITH: UNKNOWN" is definitely not the problem in my case. The files are perfectly valid MP3s and iTunes correctly shows them as encode with lame.
Besides, it doesn't affect whole albums for me, but definitely more 50% of the tracks.
I just re-encoded an album which had 7 of 11 tracks failing on the iPod. I used the exact same process as originally (lame 3.97, picard, mp3gain). Interestingly all tracks worked then.
I then restored the iPod and mass-imported my whole library again. Now the tracks don't work anymore again. So there might be some problem with mass-importing. (The files on the iPod disk still seem to be OK though, they still work everywhere but on the iPod).

I've submitted a lengthy bug report via http://www.apple.com/feedback/ipod.html , but I doubt I'll get some feedback from that.