My every day phone is an 830 with Denim , been playing with a 640 with the 218 update. Went to sync content of phones , email, contacts sync no problem . When I went to play my saved songs on Xbox music they were not on the sd card where I had stored them . I do regular backups, my documents and Photos are still there and in One Drive. I connected my 830 to my laptop to see what was there but the music folder is empty. A little annoyed I lost about 150 songs. Any Ideas what happened ?