Sunday, September 23, 2012

VirtualBox on Mac Lion 10.8.2

Over the past few months I've been using VirtulBox on my new MacBook Pro.  Absolutely love the combination!

Yesterday I finally upgraded the MacBook from 10.8.1 to 10.8.2 and immediately VirtualBox stopped working.  Instead of opening my VMs, I was greeted by the message:

Failed to open a session for the virtual machine Windows XP.
VT-x is being used by another hypervisor. (VERR_VMX_IN_VMX_ROOT_MODE).
VirtualBox can't operate in VMX root mode. Please close all other virtualization programs. (VERR_VMX_IN_VMX_ROOT_MODE).
 Turns out this is a new bug tracked at

It is fixed using HotFix package 4.2.1 for Virtualbox available at

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