My friend's MacBook Pro seems to have a duff internal drive. It won't start up, and the Recovery Assistant Disk Utility fails to verify it. I can replace the drive easily enough, but can I remove the data from the dead one still in the machine, or do I need to buy a caddy? I tried to Restore it to an external drive, but that failed saying the source was invalid. I've connected it to wifi, but I don't see it in the Shared section of Finder, where my other Mac is.