All music gone from iTunes and when trying to put it back, "Attempting to copy to the disk Macintosh HD failed. The disk could not be read or written to."
Hello,
I have a portable 500gb HD and I use it to put music and other stuff.
Earlier, out of the blue, all of my music from iTunes disappeared, and I tried to put it back by dragging my folder "music" from the external HD to iTunes, but the message "Attempting to copy to the disk Macintosh HD failed. The disk could not be read or written to." appears and nothing happens. Only 40 albums (the same ones every time) go into iTunes before the message appear.
I tried restarting the computer and nothing happened.
MacBook Air (13-inch Mid 2012), OS X Yosemite (10.10.2)