What happens when you Sysprep a system running Hyper-V on Windows Server 2008 R2?

The short answer is: Everything just works.

The long answer is as follows:

Prior to Window Server 2008 R2 (namely in Windows Server 2008) you could run into a couple of problems.  In Windows Server 2008 R2 Microsoft has implemented a Sysprep provider to ensure that everything goes smoothly.  This provider does work during two of the phases of Sysprep:

Generalize

The generalize phase of Sysprep is where an installed version of Windows is prepared to be duplicated – and all installation specific information is removed.  During this phase Hyper-V makes a couple of key changes:

• The installation date information for Hyper-V cleared.  It will be automatically regenerated when the system image is deployed to a new system (or rebooted locally).
• The dynamic MAC address range is cleared.  This will also be automatically regenerated when the system image is deployed to a new system.  This step is necessary to ensure that you do not get duplicate MAC addresses on multiple Hyper-V servers if they are all deployed from the same base image.

Specialize

The specialize phase is run after the system image has been deployed to a new computer.  Hyper-V makes the following change as part of this phase:

• Enable automatic launching of the hypervisor in the boot configuration data (BCD) store.  Because a new boot configuration data store is created as part of the image deployment process, and because Hyper-V stores information in the boot configuration data store – we need to make sure this information comes across to the new system.

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