How can I fix Virtualization not being available in bootcamp windows? Virtualbox complains that VT-x isn't available and running securable confirms that it's not available. My 2012 rMBP has an i7 and intel clearly states the CPU does have VT-x, nevermind the fact that Virtualbox works just fine under OSX. This is where if I had a PC I'd check if it was enabled in BIOS.

What can I do?
Okay so I got it working with virtualbox with the help of VMWare. I tried AnonymousAppDev's answer but it didn't have any effect on my machine (at least not after the first reboot).

I read that VMWare may be able to turn on VT-x, so I installed VMWare workstation. That in turn asked me to remove Hyper-v since there's a conflict. After rebooting securable now says I have VT-x enabled and I'm able to run Virtualbox.