That Sansa was in MSC mode and has their latest firmware?
Also another acquaintance had that issue so we tried it with some MP3s ripped from an original CD with "CDEX" using the stock settings. These played fine. I could not help them with their downloaded Mp3s since they were from Limewire. My guess is they were badly encoded.
I'm looking for an inexpensive MP3 player onto which I can copy mp3 files directly from my PC hard-drive, rather than using a subscription service. Any ideas? I currently have a Sansa M200 series - it copies it, but then doesn't list it under 'Play All'.