Download the installation file of the OS that you need. OS X Lion, Mountain Lion and Mavericks are downloadable from Mac App Store. Go to the machine’s setting and choose System tab, find the setting for Chipset and make sure PIIX3 is selected there. When you’re done with creating the virtual machine, do NOT run the machine yet. As a little tip, I use 20 GB virtual storage for Mountain Lion installation, but of course this will depend on what you are planning to do with the guest OS. The next step is to create a new virtual machine. If you haven’t heard about VirtualBox, you can start from here.Īfter you have VirtualBox installed. It’s one of the best virtualization software from Oracle, and it’s legally free.

Use this guide at your own risk.įirst, I assume you already know about VirtualBox. As a bonus, I will add guides to install OS X Mavericks as guest OS too, but I haven’t tested running Mavericks as guest OS.ĭisclaimer: This guide is provided as is, without any guarantee. The VirtualBox version that I use is 4.3.6. I have used these steps to install OS X Mountain Lion (as guest) in my Mac mini running OS X Mavericks (as host). So the host machine MUST be OS X since it’s the only way to run legal OS X.

I am talking about running these OS legally, not about Hackintosh. This article provides step by step guide on installing OS X Lion or OS X Mountain Lion on VirtualBox as guest OS. And buying a separate machine for each OS that we need is simply not the best solution. Sometimes, our work requires us to use different operating systems.

Virtualbox extension pack 4.3.6