Hyper-V VM Unable to Start

This is an error that is unlikely to occur for most of us because our servers are relatively up to date, but I work with training centers that use workstation images which are not updated on a regular basis. Today I helped a training center resolve a problem with a Hyper-V virtual machine that would not start.

Scenario:

• Windows 2008 R2 (not SP1)
• New hardware
• The OS image with VM worked fine on older hardware

The errors:

• An error occurred while attempting to start the selected virtual machine(s). <virtual machine name> could not initialize
• <virtual machine name> could not initialize. (Virtual machine ID <virtual machine GUID>)
• <virtual machine name> Failed to set/change partition property

The problem occurs only for new hardware because some newer Intel processors support AVX instructions (http://software.intel.com/en-us/articles/introduction-to-intel-advanced-vector-extensions/) and Hyper-V in Windows 2008 R2 RTM, doesn't know what to do with them.

The simple solution is to install Windows 2008 R2 SP1. However, there is also a hot fix and WMI workaround for Windows 2008 R2 RTM. You can view the Microsoft knowledgebase article with the hotfix and workaround here:  http://support.microsoft.com/kb/2517374