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Easy VMDK conversions

VMDK to VHD Converter opens the door to easy VM conversion.

If you're already running and working with VMware virtual machines and would like to see how your VMs (virtual...

machines) perform on other virtualization engines, then you may want to take a look at the tool VMDK to VHD Converter.

This tool allows you to convert VMware virtual disk files to the Microsoft Virtual Hard Disk (VHD) format. In addition to allowing the virtual disks to be recognized by and run on Microsoft Virtual Server, you can also import the converted VHD files to Xen-based virtual machine host systems. One Xen-based virtualization vendor, Virtual Iron, has already noted how to use VMDK to VHD Converter to convert VMware VMs to VMs that can run on the Virtual Iron virtual infrastructure. For more information on using this tool to convert a VM for use on a Virtual Iron platform, see Virtual Iron CTO Alex Vasilevsky's blog post Converting VMware Virtual Appliances for Use with Virtual Iron.

VMDK to VHD Converter is a very simple tool to use for disk conversion. To get started, first download and install the Microsoft .NET Framework 2 (if it is not already installed). Then download VMDK to VHD Converter from Next, extract the zipped contents from the file. Once the tool is extracted, follow these steps to convert a VMware .vmdk virtual disk to a .vhd virtual disk:

  1. In Windows Explorer, double-click on the Vmdk2Vhd.exe file.
  2. You should now see the Select VMware Virtual Hard Disk dialog box. Browse to and select the disk to convert and then click Open.
  3. Now in the Vmdk2Vhd dialog box, click the Save As button, browse to the desired location of the new vhd file, enter a file name, and click Save.
  4. Click the Convert button to start the disk conversion process.
  5. When the Conversion Completion dialog box appears, click Yes if you have another disk to convert, or click No if you are finished.

At this point, you have the hard disk for the virtual machine ready to go. You will then just need to create the new virtual machine and select for the VM to use an existing virtual hard disk.

Now if you're thinking "That was almost too easy," you're right. Taking a Windows VMware VM disk and just trying to run it as a Virtual Server VM will likely result in the VM not even being able to boot. This is because of differences in the emulated hardware and drivers between VMware and Virtual Server. Of course, if you're just cloning a data disk, then this will not matter. However, if you wish to clone a system disk, then you're going to have to do a little work prior to cloning the disk.

To prepare a VMware virtual system disk to run in a Virtual Server or Virtual PC environment, follow the procedure documented in my article How to migrate VMware virtual machines to Virtual Server. This procedure will walk you through the steps of removing the VMware Tools, disabling drivers in the registry, and updating the HAL and kernel prior to converting the .vmdk disk to a .vhd disk.

Moving a virtual hard disk from one virtual environment to another has to be looked at like moving a hard disk from one physical server to another server with different hardware. Even with differences in how the virtual environments present hardware to the virtual machines, with the right preparation beforehand, you should have little trouble cloning a VMware disk to the .vhd format and successfully running the VM on another platform.

About the author: Chris Wolf is a Microsoft MVP for Windows Server – File System/Storage and is a MCSE, MCT, and CCNA. He's a Senior Analyst for Burton Group who specializes in the areas of virtualization solutions, high availability, enterprise storage, and network infrastructure management. Virtualization: From the Desktop to the Enterprise (Apress), (Addison Wesley) and a contributor to the Windows Server 2003 Deployment Kit (Microsoft Press). Reach him at

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