It happened that the usual compact disk from Hyper-V Console doesn’t seem to be effective on one of my .vhdx file. Looking around on the web, I discovered that it is a quite common problem. The solution is to open a Powershell window with administrative access rights, and use the following command: optimize-vhd <offline Hyper-V disk file> -mode full For further details about this command, … Continue reading HOWTO compact vhd/vhdx Hyper-V files »