I took the hard drive out of my old macbook pro, bought a 3.5" SATA enclosure, and hooked my new macbook pro up to it w/ a usb cable. Whenever I turn the enclosure "on" I get this error message: "The disk was not ejected properly. If possible, always eject a disk before unplugging it or turning it off." All I can hit is the "okay button". :/ What can I do to get all my old important files off?