The guide below tries to explains how to easily install Mac OS X Yosemite 10.10 in a virtual machine using VirtualBox. It's based on this pastebin which I found via Google, adjusted to work with Yosemite. Legal disclaimer: Make sure to perform the following steps on a regularly purchased Apple computer, running a genuine OS X (host) operating system. How-to Preparation Download OS X Yosemite from
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