FIX : Error 0x000000C4 Unable To Install Windows 8.1 on VirtualBox

We all know that when a beta version is out for any operating system, most of the advanced users try it using virtualization. As soon as we got the Windows 8.1 64-bit Preview in our hands, we created a bootable USB of its ISO image and tried to mounted it on a computer but then we came across an unexpected error. Here is the screenshot of that error:

Your PC needs to restart. Please hold the power button. Error code : 0x000000C4

The solution to the problem is this command:

Open administrative Command Prompt and paste following command followed by Enter:

"c:\Program Files\Oracle\VirtualBox\VBoxManage.exe" setextradata [vmname] VBoxInternal/CPUM/CMPXCHG16B 1

You have to replace vname with the name of your Virtual Machine which you can find in the VirtualBox interface or with this command:

"c:\Program Files\Oracle\VirtualBox\VBoxManage.exe" list vms

Don’t forget to set the VM name in quotes if it contains blanks. The command enables the CPU instruction CMPXCHG16B. More info here.