I just got my MacBook Air back from AppleCare. They replaced the Logicboard and when I booted it up it was fine. However, in the meanwhile I have purchased a new MacBook Pro, and I just want to replace everything on the MacBook Air, and so I booted up of a USB stick with Mavericks (which has worked fine in other Apple laptops), and reformatted the SSD. I then selected to install OSX, but all that happened was that I got a message that "OS X Mavericks cannot be installed on this computer"??? We are talking a MacBook Air from 2012 here, the 13", i7 version. It was running Mavericks 10.9.3 before, so there really is something wrong. What should I do?