Windows Server 2008 and Windows Server 2008 R2 may hang on boot with the Hyper-V role enabled

Applies to: Windows Server 2008 StandardWindows Server 2008 EnterpriseWindows Server 2008 Datacenter

Symptoms


Consider the following scenario:

Install Windows Server 2008 or Windows Server 2008 R2.
Enable the Hyper-V Role under Server Roles.
The machine hangs or encounters a 0x3E bugcheck (MULTIPROCESSOR_CONFIGURATION_NOT_SUPPORTED) after you restart the machine.

Cause


On a system with Mixed Processor Steppings, the Memory type range registers are not consistent across all the processors.  When the Hyper-V role is enabled, this can cause system instability.

Resolution


Ensure that all Processor Steppings are consistent (MTRR Capabilities) across all processors that are installed on the system. 

More Information


It is not recommended to have processors with Mixed Steppings installed if you are intending to install and enable the Hyper-V Role on Windows Server 2008 / 2008 R2.