Thanks for the swift reply Old Listener!
My music library has always containted loads of WMA, from way back before I even knew about Media Jukebox... Most of them are CD rips, some of them are downloads or given to me by friends, all of them work on other platforms.
When I organise my library by file type, none of the ones with file type WMA play, it instead skips to the next non-WMA file...
Am I the only person to experience this? If I uninstall/reinstall, will I lose my playlists?