I have been having this issue a while now, when i choose music from my music collection to offline sometime it freezes.
I tick the songs i want, choose download and then i get 'loading' scrolling across the top of the screen, nothing happens and then the store closes.
you then cannot get back into the store until you reboot the phone. After a reboot it will then work, i have been trying to figure out what is causing this?
here is what i have tried:
replaced my class 4 micro SD with a class 10 Samsung one
tried offlining only over moble data, not wifi
i had it happen just now, i managed to offline 3x albums, no issue went to offline a 4th, this time it did do something different... it offlined half the album i could see the progress off the tracks downloading it suddenly stopped and the download bar didnt move, the whole app stopped responding to touch and then closed.
whilst this was happening, the rest of the phone functions fine i had music playing over bluetooth and that carried on no issues! so i know its something to do with the windows store.
any suggestions, would be great I thought the factory reset would sort this but it didnt! I was hoping to pull some logs off for the MS Support team on twitter but they said that isn't possible