My Xtra exhibits a “playback error” when trying to play certain mp3s. The resolution is to use foobar2000 to re-encode these mp3s. Specifically, click “File / Open” and open the respective mp3. Before you get started, you’ll need lame.exe. Extract the contents of the .zip file anywhere on your hard drive, then copy/paste lame.exe anywhere, for example in the foobar2000 folder. In the following steps, when prompted for lame.exe, browse to where you pasted it.
In the two versions of foobar2000 I’ve used, the track starts playing automatically, so stop playback if that’s also the case for you. Right-click on the file (the item in the playlist), click “Convert” from the menu, then click “Convert to Same Folder”. Choose “MP3 (LAME), 190 kbps, V2, fast” from the dropbox then click OK. Click “Yes” in the warning window that tells you there will be quality loss. Your newly-created mp3 will have a different filename and a newer timestamp than the older one. This newer one is (obviously) the one that should be copied to the Xtra.
The only problem I’ve observed is that sometimes, not always, the converted mp3 isn’t able to be fastforwarded or rewound, if those words still apply in the digital world. In other words, once you start playing the track, if you try to fastforward or rewind it, you’ll have to start over, so be cautious. I haven’t looked into that problem – I’m leaving good enough alone, or whatever the saying is.