I keep my itunes library on my external harddrive, but now i want to put it back on my macbooks harddrive. however, every time i am transferring it to my macbook, it stops after a while and tells me that the files already exist on my macbook even though i delete the itunes folder on my macbook before starting the transfer. sometimes it will do it with a certain song, but most of the time it says this (pic). help please?