Hi,
I'm trying to export playlists on rekordbox to USB so i can play on cdj2000. I have exported the playlists using sync manager & get an error message saying some files have not been exported. When i plug in to CDJs the playlists do not show but all songs are in individual files under a contents folder & some are in a folder called unknown artist This makes it annoying as i can not sort my music.
However, when i go into rekordbox & click the device it says they are in playlists. I have attached screenshots below 
Post is closed for comments.
I had exactly the same issue a few days ago, think it was due to Rekordbox still analyzing my tracks at the same time I was exporting, it actually finished exporting before it finished analyzing. I formatted the USB and exported again and everything worked fine again.
...or you have some songs without an artist tag (hence the unknown artist folder).