I needed IE8 to perform a certain task and downloaded the image online.  It came in a .ova format.  First install 7zip and extract the information from .ova and you will be left with a vmdk file

Perform the following on the Hyper-v server 2012 R2 or greater.  I could not get some things installed on Windows 10

Download and install Microsoft Virtual Machine Converter 3.0:

Open Powershell and run the following commands:
Import-Module ServerManager
Add-WindowsFeature BITS-Compact-Server

Install Visual C++ Redistributable for Visual Studio 2012 Update 4 update from here
I installed both x64 and x86 versions

Open Powershell and run the following commands:
Import-Module "C:\Program Files\Microsoft Virtual Machine Converter\MvmcCmdlet.psd1"
ConvertTo-MvmcVirtualHardDisk -SourceLiteralPath "C:\yourfile.vmdk" -DestinationLiteralPath "C:\yourfile.vhdx" -VhdType DynamicHardDisk -VhdFormat Vhdx

Read on if you get an error similar to this:
The entry 00000000-0000-0000-0000-000000000000 is not a supported disk database entry for the descriptor

To fix this we need to comment out the items that are not supported by Hyper-v
Download these tools from here http://www.softpedia.com/get/System/Back-Up-and-Recovery/dsfok.shtml

from command prompt do the following on the .vmdk file:
dsfo.exe "D:\PathToVMDK\disk1.vmdk" 512 1024 descriptor.txt

You will then have a text file that says descriptor.txt
open that file and comment out the following lines:

#ddb.comment = “”
#ddb.uuid.image = “024d091c-2902-42a3-93b2-17f8cd4c0947”
#ddb.uuid.modification = “6ab801a7-316d-4562-b91a-0dd19e781153”
#ddb.uuid.parent = “00000000-0000-0000-0000-000000000000”
#ddb.uuid.parentmodification = “00000000-0000-0000-0000-000000000000”

Save the changes then use this command to load the file back into the vmdk:
dsfi.exe "D:\PathToVMDK\disk1.vmdk" 512 1024 descriptor.txt

No try the convert command again and if it still errors out perform these steps again to extract the descriptor file, edit out non supported entries, and import back in the vmdk