Hi LUG, I read that using 10.8 is preferable to later OS X versions when booting from an external hdd. I've been running Logic 9 and Yosemite on an external drive while using a borrowed i7 laptop. And I'd appreciate advice from the group about the wisdom of that. Of course, internal is better, but I've been trying to keep files off the laptop until I get another machine. Thanks very much.