Hi, I use Yosemite and have itunes Match that has saved about my 5000 songs on the apple cloud. I tried to create a new library by pressing the option key while launching Itunes and then created a new library on the external (ExFat format) drive (usb). However after saving the library itunes refuses to launch and gives the following error message: the itunes application could not be opened. An unknown error occurred (13008) How do I backup all my itunes match songs onto my external usb drive? Kindly assist. Thanks!