Convert OVA to VHD for usage in Hyper-V

Quite easy actually, install VirtualBox that comes with the program VBoxManage.exe. It can be used with clonehd to specify the new format of the disk. You specify the original disk file, in this case the .vmdk, and then give a location and name to output the .vhd.

Open a cmd prompt, CD to C:\Program Files\Oracle\VirtualBox or Virtualbox install directory and then run:

VBoxManage.exe clonehd --format vhd "C:\temp\VM\disk1.vmdk" "C:\temp\VM\disk1.vhd"

Documentation for VirtualBox: https://www.virtualbox.org/manual/ch08.html#vboxmanage-clonevdi

Then I created a new virtual machine from Hyper-V Manager and selected "Use an existing virtual hard disk". Worked perfectly.

Use this guide for internet access:

https://superuser.com/a/472854/405096

I can't comment yet, but this is a followup to the comment of Ogglas

If you get the message:

'VBoxManage.exe' is not recognized as an internal or external command, operable program or batch file.

Try to enter the entire path of VBOXManage.exe in my case, that would be:

B:\Virtualbox\VBoxManage.exe

The new command would then be:

"C:\Program Files\Oracle\VirtualBox\VBoxManage.exe" clonehd --format vhd "C:\temp\VM\disk1.vmdk" "C:\temp\VM\disk1.vhd"

Source: https://serverfault.com/questions/365423/how-to-run-vboxmanage-exe