A few days ago, I was migrating a couple of legacy virtual machines from Virtual Server to Hyper-V. I used Matthijs ten Seldam’s VMC to Hyper-V Import Tool to save some time on the import process, although it is an import tool (not a migration tool), so I did need to move the .VHDs manually.

I realised that I’d forgotten to remove the Virtual Machine Additions before I shut the machines down in Virtual Server but I figured I would be able to do that in Hyper-V, before installing the Hyper-V integration components. Unfortunately, that didn’t work for me and attempting to uninstall the Virtual Machine Additions from the Control Panel Add or Remove Programs applet resulted in the following error message:

Virtual Machine Additions

{\Tahoma8}You can install Virtual Machine Additions only on a virtual machine that is running a supported guest operating system.

followed by:

Add or Remove Programs

Fatal error during installation.

A little bit of googling turned up a TechNet Social thread, where Tim Cerling explained that:

“You can only install the Virtual Machine additions from within Hyper-V if the virtual machine is running Windows XP SP3, Windows Vista SP1, Windows Server 2003 SP2 or Windows Server 2008 and the additions are version 13.803, 13.813, or 13.820. If the operating system is different or the additions are different, they can only be removed from Virtual Server or Virtual PC.”

Clicking on the support information in Control Panel’s Add or Remove Programs applet told me that my Virtual Machine Additions were still at 13.552.0.0, so I had to load the VHD under Virtual Server to remove them, before copying the .VHDs back to Hyper-V (I could use the same virtual machine configuration that I had created earlier but had to remove the disks and add them again in order to assign the appropriate permissions).

After starting the VMs, I cancelled the Found New Hardware Wizard and installed the Hyper-V integration services (including an automatic HAL update and a couple of reboots). Because I’d used legacy (emulated) network adapters and allocated static MAC addressing (carrying forward the MAC addresses from Virtual Server), the guest operating systems didn’t notice that the underlying NIC had changed and so it wasn’t necessary to reconfigure TCP/IP settings.