Hyper-V and VirtualBox on the same computer

You can only run one or the other; not both at the same time. When I tried running a VM on VirtualBox on my Windows 8.1 machine, I got this error:

“vt-x is not available”

This post in the VirtualBox forums was my first indication that you can’t have 2 hypervisors running at the same time: http://ift.tt/1vRwgFG

This post is a solution that has worked for me:

http://ift.tt/1dQvWhx

In short, you create a new boot profile that disables Hyper-V in Windows 8.1 (covered in the Hanselman blog post). It’s actually kinda slick. When you click “restart”, hold down the Shift key and the menu will come up where you can select a different boot profile.