VHD stands for Virtual Hard Disk, is a disk image file format which stores the entire content of a virtual machine (an operating system installed on software). Besides, virtual hard disk contains file system (NTFS, FAT, exFAT, UDFS) and partition similar to physical hard drive. Apart from this, VHD file extension is being widely used for creating system image backup.

• Windows Vista complete PC backup- This feature was introduced in Vista OS to create an image for a hard drive. Thereafter, this disk image backup gets stored in virtual hard disk file (VHD).
• Windows XP Mode on Windows 7- Microsoft introduced Windows Virtual PC as a virtualization application with the help of which you can run Win XP (virtual machine) on Win 7 (host machine). The Virtual machine’s data gets saved in VHD file extension on Win 7.
• Windows Disk management & DiskPart- With disk management utility, you can create & mount VHD like a physical drive. Once the VHD is attached, you can copy file to & from a virtual drive. In addition, VHD file can be created by a command line tool DiskPart.
• Microsoft Virtual Server & Hyper-V- VHD File format is used by Microsoft Virtual Server and Hyper-V hypervisors to store their Virtual Machines. You can run multiple operating system (referrred as Guest OS/virtual machines) on a single host machine.

The VHD file belongs to the category of Disk Image Files.

The following applications create and open VHD (virtual hard disk) file.

Microsoft introduced VHD file with Windows Vista and Microsoft Virtual Server. The primary purpose of VHD file is to create backup of disk image and achieve virtualization environment.

application/octet-stream

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The default location of VHD file depends on what virtualization application is installed in the system. For each application, the default location will be different:

Microsoft Hyper-V

• C:\Users\Public\Documents\Hyper-V\Virtual Hard Disks

Windows Virtual PC

• C:\Users\xxxx\AppData\Local\Microsoft\Windows Virtual PC\Virtual Machines\Windows XP Mode.vhd

Microsoft Virtual Server

• C:\Documents and Settings\All Users\Shared Documents\Shared Virtual Machines\virtual machine name