Virtual Box and Hyper-V VHDX file format

VirtualBox, my favorite virtualization app, does not support VHDX file format as a file for virtual disk.
To convert the file to a VHD file, a HyperV is needed to import the content of such file to a new VHD file you can create for a new machine in VirtualBox.
I created the VHDX using Disk2VHD in order to load backup the server and load it to my main development PC, so after the load I can delete the VHDX file.

This article by Anurag Gawande explains how to do this:
http://blog.anuragg.com/2012/10/vhdx-to-vhd-conversion.html