Converting a VHD to a VHDX

In Windows Server 2012 / Windows 8 we have introduced a new virtual hard disk format called “VHDX”.  There are a number of advantages to this format:

  • Support for greater than 2TB disks
  • Better performance for dynamic and differencing disks
  • Better handling of different disk sector sizes
  • And more…

But what if you have a collection of VHD files?  Luckily, converting to a VHDX format is simple (though potentially time consuming).  To do this – all you need to do is:

  • Open the Hyper-V Manager
  • Select Edit Disk… from the action pane (or from the Action menu)
  • Click Next to get past the introduction page of the Edit Virtual Disk Wizard
  • Enter the name and location of your existing VHD file on the Location page and click Next
  • On the Choose Action page select Convert and then click Next
  • On the Choose Disk Format page select VHDX and click Next
  • Complete the rest of the wizard and select the options you want

This will then create a new VHDX file that is a copy of your existing virtual hard disk.  You can actually use the same process to convert a VHDX file back to a VHD file (if you needed to move it to an earlier version of Windows).