I have a Clip Zip with USB mode set to MSC. I (mostly!) have no problem at all dragging files across and listening to them.
But some mp3 files are not recognised by the player. I don’t think this is a DRM problem, as the problem occurs on free content.
Once (just once) the problem was solved by dumping the file into Audacity and then exporting it again. But every other time I’ve tried this trick it hasn’t worked.
I once found that a voice memo I’d recorded on the Zip, when converted in Audacity from WAV to MP3, then failed to be recognised.
Here are two examples of files that aren’t recognised by my Clip Zip. Podcasts, the most recent as I type this is #44, of Empire (the movie magazine)
also this free Big Finish drama called “The Coup”
It’s as it they aren’t on the player at all. But, when USB connected, the files are clearly listed and can be played through the computer’s speakers.
Am I missing something obvious?!
all best regards