I have a Sansa Clip+, using it in MSC USB mode to get my music to it with Rhythmbox, and I noticed that none of my songs with non-ASCII chacters in the filename show up in any of my playlists. They work and display perfectly fine when I do “Play All”, or access them under “Artist” or any other way.
Browsing directly to my Clip+ filesystem, I see an .m3u file for each of my playlists. They’re all formatted like this (here’s an example):
#EXTM3U #EXTINF:,Close Combat
MUSIC\ParagonX9\ParagonX9\01.01 - Close Combat.mp3
#EXTINF:,?? -Æternity Remix-
MUSIC\Æternity\Aural Sky\08 - \_\_ -Æternity Remix-.ogg #EXTINF:,Point Of No Return MUSIC\CarboHydroM\Rock'n Twinbee\07 - Point Of No Return.ogg #EXTINF:,Attack
MUSIC\30 Seconds to Mars\A Beautiful Lie\01 - Attack.mp3 #EXTINF:,estha - Into the Wind
MUSIC\ALiCE'S EMOTiON\Crevice -クレヴィス\05 - estha - Into the Wind.ogg
#EXTINF:,Space Beacon
MUSIC\radiantx\Digital\_ A Love Story\00 - Space Beacon.mp3
Neither “?? -Æternity Remix-” or “estha - Into the Wind” show up in this playlist when I play it on the Clip+.
My Sansa Clip+ reports that it has firmware Version V01.02.15A. It said that since I got it, and I did the instructions to update it to V01.02.15, but it still shows as 15A. Guessing that’s normal.