Keep in mind that Hyper-V creates dynamically expanding virtual hard disks. This means that the hard disk only takes up as much room as needed and can only grow to the specified size. For example, clicking the Inspect button (next to the Edit button in the Hard Drive section) displays the Virtual Hard Disk Properties dialog box. As you can see, at this point the size of the virtual hard disk file is 4MB. As I install the operating system and applications, the virtual hard disk will grow in size until it reaches the maximum size of 500GB.
Credit: Images by Greg Shultz for TechRepublic