Windows Virtual PC and Windows XP Mode no longer require HAV processors

The Virtual PC team is thrilled to announce the availability of KB977206 which allows our customers to use Windows Virtual PC and Windows XP Mode on non-HAV (Hardware-Assisted Virtualization) machines.  Windows XP Mode continues to use hardware virtualization such as Intel Virtualization Technology (Intel® VT) or the AMD-V™ chipset when available but it no longer requires them.   A number of our customers and partners have been asking us to support a wider range of PC’s including those without HAV capability and we have delivered this software patch to address their needs.  We believe that this change simplifies the customer experience and makes this benefit accessible to many more PCs.

Download the software update for 32-bit host operating systems from here and for 64-bit host operating systems from here.

The KB article describes the various scenarios under which the software update must be installed. Ensure that Windows Virtual PC is installed before applying this fix.

Some FAQ’s around this update:

Q: How do I check the HAV capability of my machine?

A: Download and run the Microsoft Hardware-Assisted Virtualization Detection Tool.  Go through the user guide for detailed description of the result.

Q: I have a machine with a HAV enabled processor, which has Windows Virtual PC and Windows XP Mode running.  Do I need to apply this fix?

A: Short Answer – No

Long Answer – The fix is primarily targeted for non-HAV machines.  If you have a functioning setup, then you can opt to not apply this fix.  However please note that this update contains the fix for the power state issue seen (with Windows Virtual PC installed) on Intel® Clarkdale/Arrandale processor ( and it is recommended that you apply this update on that specific hardware.  If you are an IT Administrator with a heterogeneous mixture of machines (HAV plus non-HAV machines), you can deploy this fix on all the machines.  The user experience and performance on a HAV enabled machine before and after applying this fix will continue to be the same.

Q: I have a machine with a HAV capable processor (i.e the HAV setting is not enabled in the BIOS yet).  Do I need to apply this fix?

A: For Windows XP Mode (or any Windows XP SP3 guest OS) users, we expect the performance to be comparable on HAV and non-HAV processors, however if you are planning to use any other guest OS we recommend that you enable the HAV setting in the BIOS rather than applying the patch.

Q: I have a non-HAV box and I wish to use a Windows Vista/Windows 7 VM using Windows Virtual PC.  Is it possible?

A: This fix is primarily targeted towards users who need to run their productivity applications in Windows XP Mode (or any Windows XP SP3 virtual machine) on non-HAV machines.  Hence you would need a HAV capable processor if you need to run a Windows Vista or Windows 7 virtual machine on Windows Virtual PC with acceptable performance.


Praveen Vijayaraghavan

Program Manager, Microsoft Virtualization Team