When you start Windows 8.1 setup from a DVD or iso file in a VirtualBox VM, you may get the following error:

This PC can’t run Windows 8.1 Preview

You can’t install Windows 8.1 Preview because your processor doesn’t support CompareExchange128.


Run the following command at the command prompt of the host computer

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

Replace the [vmname] with the name of the virtual machine.

Happy system administration.


[SOLVED] VirtualBox error CompareExchange128: This PC can’t run Windows 8.1 Preview

Karim Buzdar

About the Author: Karim Buzdar holds a degree in telecommunication engineering and holds several sysadmin certifications. As an IT engineer and technical author, he writes for various web sites. He blogs at LinuxWays.

Leave a Reply

Your email address will not be published. Required fields are marked *