Problems with Intelppm.sys and processr.sys under Virtual PC / Virtual Server

Under certain circumstances with a Windows XP / 2003 operating system - intelppm.sys and processr.sys can cause a virtual machine running under Virtual PC / Virtual Server to crash (by default this will cause the Windows guest operating system to reboot automatically - but if you have changed this setting you will see a blue screen).  The reason for this crash is because these drivers are attempting to perform an unsupported operation inside of the virtual machine (like upgrading the physical processors microcode, changing power state on the physical processor).

Today this problem only occurs on Centrino and AMD K8 processors.  Most people see this problem when they move a virtual machine that was created on another type of processor to a computer running one of these types of processors (and then they usually see the problem when they attempt to shutdown their virtual machine for the first time).  Now you may be wondering why you have not heard about this problem more often - and the reason for that is that if these drivers fail once - they are smart enough to not attempt to perform the operation that failed again.

If you are seeing this problem repeatedly you can manually disable these drivers (with no negative side effect) by going to the following location in the registry:




And changing the 'Start' value to '4'.

In the mean time we have made some subtle changes to the way our hardware exposes the processor in Virtual Server R2 so that in future products these drivers should never get loaded inside of virtual machines.