When using VMs and Windows 2008 you have the ability to easily grow the C drive on your servers. This makes it much easier to assign only the space needed to the C drive of your servers saving you a ton of space.
However I recently had a few machines say that the disk was extanded in Computer Manager and diskpart, but Windows Explorer (aka My Computer) showed the old amount. And growing the disk a second time doesn’t help. Shrink the partition (either in diskpart or Computer Management) then extend it again seamed to fix it for me.