Microsoft has kindly released Virtual Machine Appliances for testing web sites using Microsoft Edge and Internet Explorer versions 8 to 11.

These VMs are also useful to test other software on a clean-slate VM.

But sometimes, the amount of HD available on the main partition of the appliance (40GB total, about 9GB free) is not enough for a particular use case.

So, if you need to resize a VirtualBox Windows appliance, here’s what you should do:

• Download the appropriate image (eg. Microsoft Edge on Windows 10 - VirtualBox platform)
• Import the OVA as a new Virtual Machine
• On the command line, access the folder where the VM was created, and issue the following commands (make sure VBoxManage is in your PATH):

  VBoxManage clonehd "MSEdge - Win10_preview-disk1.vmdk" cloned.vdi --format vdi
  
  VBoxManage modifyhd "cloned.vdi" --resize 102400  

• Now, change the VirtualBox VM to use the “cloned.vdi” file as hard drive instead of the original .vmdk.
• Start the VM
• Go to “Computer Management” and extend the primary partition to cover all drive space

You should have a 100GB main HD in the VM now.