I have added .wma music files to my Duo as well as my .wpl playlists. I have since been searching the app store for a simple music player that will acknowledge my music files and playlists. Many of them look like they would work great and will play the music files. However in the playlist section of the various apps it will show my synced playlists but always says “0 songs”. I have contacted several of the app developers and they say that their apps will do what I want and that it would be the device that is causing the glitch. They think it is most likely the Duo that is not delivering the playlist .wpl info correctly. Has anyone else had this issue and maybe a work around? I wish Microsoft would have an actual music app for the Duo like Groove Music etc…