In a previous post, I talked about the new method now available for certain VMs running on a Windows Technical Preview or Windows 10 host. The list of supported guest OSs has grown:

  • Windows Server 2012
  • Windows Server 2008 R2
  • Windows Server 2008
  • Windows 7
  • Windows 8.1
  • Windows Server 2012 R2
  • Windows 8

There are prerequisites for applying KB3004908. These include:

Updating Integration Components via the Windows Update facility has created an interdependency between the host OS release version and the guest OS. There is a Hyper-V integration component called Hyper-V Data Exchange or KVP (keyword-value pairs). This component creates a shared registry key between the host and guest:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Virtual Machine\Guest\Parameters

I check this from my Windows 10 Preview VM with PowerShell:

The two properties which are used to determine the Windows OS version are HostingSystemOsMajor and HostingSystemOsMinor. In this example, my host system is 6.3 or Windows 8.1. Windows version numbers map to release names as follows:

The Windows Update facility checks these version numbers to determine if it can update the Integration Components. If KVP has not been enabled, these registry keys will not be created and thus the update will not be offered. You can check via the Hyper-V Manager or a WMI script to determine if Data Exchange is enabled:

So make sure your Data Exchange is enabled and enjoy the new Windows Updates.

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