VHD Resizer changes the size of the VHD, but not the size of the NTFS partition. Thus, if you access the VHD through a virtual machine, you just see a larger disk with additional unpartioned space. You have to use a partition management tool, like diskpart, to extend the partition. Only then can you make use of the full capacity of the virtual disk. Diskpart is a Windows command line tool.
Extending a partition with diskpart is very simple:
Launch diskpart on a command prompt.
Type “list volume.” This gives you the number of the volume that you want to extend.
Type “select volume volume-number.“
Download VHD Resizer from here