greetings iklas, and welcome to Apple discussions !
check if you have read & write permissions for your iTunes music folder. in finder, right-click on it and +get info+. unlock the little padlock (you may have to enter your admin password) and change the permission settings. next, click on the little gear-shaped icon and +apply to enclosed items+ like so
you may also give
everyone read & write access. if this doesn't help, try the same on your iTunes folder (not just the iTunes
music folder).
any help ?