I've update to 8.4 now I have 14GB in "other", and all of my music was erased.
I updated my phone a few days ago, and yesterday I asked siri to play all my music shuffled and it responded with "Your music library is empty". So I go home and plug my phone up, and it said I had no music, but there was 14GB in "other". So I put my music back onto the phone thinking that "other" was my music and I just needed to re-sync it. After it finished it still had 14GB of "other" and 12GB of my music.
Did iOS 8.4 take up that much or is something wrong?
iPhone 6, iOS 8.4