Migrating to Hyper-V from Virtual Server or Virtual PC - Tips and Suggestions

Now that you’ve decided to take the leap and migrate your Virtual Server 2005 R2 or Virtual PC environment to Windows Server 2008 Hyper-V; Welcome! I know you’re going to love it!

Some of the hurdles that you can run into may be a little worrisome, but we promise after you read through this, you’ll have the knowledge you will need to conceive a well thought out migration plan.

There are several step-by-step guides out there that walk you through the points and clicks needed to get the migration done, but the focus of this blog is to work through some of the steps that will help in the migration process. Here we go!

1. Before migrating Virtual Machines (VM)s from Virtual Server 2005 R2 SP1 or Virtual PC, you are going to want to make sure that the machines can take advantage of the Hyper-V Integration Services. Integration Services are software components that are installed in a guest running in a Hyper-V Child partition that allows the guest to more effectively integrate with the Parent partition and the hypervisor.

For example, that Windows-for-Workgroups 3.11 VM you’ve been nursing along won’t be able to take full advantage of the features in Hyper-V, however, these Operating Systems can:

  • Windows XP SP3 (x86 & x64)
  • Windows Vista SP1 (x86, & x64)
  • Windows Server 2003 SP2 (x86 & x64)
  • Window Server 2008 (x86 & x64)

Other OS’s can run in Hyper-V but they may not be able to take advantage of the Integration Services and will have to rely on legacy or 'emulated' device support. It is recommended that all pre-requisites (Service packs) be downloaded and installed before beginning the migration to Hyper-V.

2. Once you’ve determined which VMs you want to migrate, you will want to uninstall all VM Additions before migrating to Hyper-V.

If you do not remove the VM Additions before migrating to Hyper-V, you may have to move the virtual machine back to Virtual Server or Virtual PC to remove them. If you are running VM Additions which are at least version 13.813, then you will be able to uninstall them after migrating to Hyper-V. Earlier versions cannot be uninstalled from the virtual machine after it is migrated to hyper-V.

3. The next thing you may want to check is HAL compatibility. For example, this HAL is compatible:


An MPS Uniprocessor PC HAL is not, and would be upgraded when the Integrated Services are installed.

If you have a non-ACPI HAL in the VM, you may change it prior to the migration. By default, Hyper-V will install an APIC MP HAL when the Integration Services are installed in the Guest. If you choose to move the VM over to Hyper-V while it has a non ACPI HAL, you will be prompted to upgrade when you first start the installation of the ICs.

Note: Keep in mind that changing the HAL in an OS will usually trigger an OS re-activation.

4. Another thing to keep in mind is what you plan on doing with the network adapter(s) installed in the VM. If you do not have a specific need to use the Intel 21140 NIC under Hyper-V, then you should also remove that device before migration.


If you do not remove this NIC, and then install the Integrated Services, everything will appear to work just fine, however, when you try to reset your static IP information using a new Synthetic NIC which is installed (provided all pre-requisites have been met (refer to Step #1),you may see the following error message:


If you encounter this scenario, follow the steps in this article and remove the old NIC. This will free up the settings to be used by the new NIC.  http://support.microsoft.com/default.aspx?scid=kb;EN-US;269155

5. You must make some storage preparations as well. Since Hyper-V does not use Undo Disks (*.vud files), you must 'commit' or 'discard' them before migrating to Hyper-V. For information on Undo disks, visit http://technet.microsoft.com/en-us/library/cc720325.aspx.

Additionally, we suggest compacting any Dynamically Expanding VHDs. For more information on compacting virtual hard disks, visit - http://technet.microsoft.com/en-us/library/cc708317.aspx

Once all of the above steps have been completed, you are ready to physically move the VHD files to the Hyper-V server or a temporary location. Remember, only the VHD can be used by Hyper-V. All of the other files used by Virtual PC or Virtual Server are incompatible with Hyper-V. 

Good luck!

Sean Dwyer
Senior Support Engineer
Microsoft Enterprise Platforms Support