So I was thinking I want to backup my music to a 150 Gig USB drive which I also use for my windows machine. I plug the the USB Drive into my MBpro. The MBpro sees the jump drive in Finder. I open USB Drive and I can see folders, I can copy from the USB Drive to my MBpro. Then I navigate to my Itunes music folder. I select copy but when I move to the USB Drive it will not allow me to Paste my music folder to the USB Drive. What am I doing wrong, why can't I backup my music?