A virtual hard drive is one of the best ways to backup your hard drive. VHDs have been in use by IT professionals for server applications and virtual machines for years now.
However, you can use them as a free, easy-to-use backup format especially if these tools come readily with Windows already.
What a VHD is a large container file that mimics the file structure of a hard drive much like a ZIP file but without the compression. Since they are single files, they make backing up your files really easy. Other benefits include cross platform and application compatibility as well as easy restores.
One thing that you need to keep in mind is that in order to use a VHD, you need to have enough space on your hard drive because that is where it resides. So, once you’re done archiving your files you can easily move it to an external hard drive.
A number of programs recognize VHD namely the VirtualBox virtual machine software and which is available for the Linux, Windows and OS X platforms. Better still, they can be accessed by local networks such as the internet, removable media or even SMB protocol.
When they are attached to your system, they can be treated as if they are USB sticks or even external hard drives.
As for using VHD, it works best when you are restoring files to the same hard drive, a larger hard drive or the same model hard drive.