Here is how i do it: - extend the vhd using hyper-V - extend the partition inside the vhd : if it is the boot partition, the you have two choices: boot with a winpe with diskpart support and do the diskpart ,...., extend or shutdown the vm using this drive connect the drive to another vm (a 2003 is better) and do the diskpart ,...., extend. if it isn't a boot partition and isn't used for pagefile then should be able to extend it using diskpart ,...., extend For the record the diskpart ,...., extend operation is described there in details.