If you sync mp3 files to /Android/data/com.bittorrent.sync on an external memory card (Galaxy S4, KitKat) is it expected that the media scanner will find them? My experience is that it does not. Initiating a media scan using RocketPlayer or simply rebooting the phone does not cause the music files to show up in Google Play or RocketPlayer. If it did, I wouldn't mind the limitiation of only syncing to /Android/data/com.bittorrent.sync (at least for media files.) This is actually a friend's phone so rooting it may be a no-go.