All about VHD files in Windows: uses, creation, and management

The VHD files in Windows (with a .vhd extension) are powerful resources within the Microsoft operating system ecosystem, specifically designed to represent virtual hard drives. Although they were created with technical purposes linked to virtualization, they are now also used for backups, data isolation, or even booting alternative operating systems.

Thanks to the tools built into Windows, especially from Windows 7 and above, It is possible to create, mount, modify and even boot from a VHD fileIn this article, we'll review everything you need to know about these virtual disks: what they are, how they work, how to create them, the different types, their advantages, and more.

What is a VHD file and what is it used for?

 

VHD stands for Virtual Hard Disk. It is a disk image that simulates the behavior of a physical hard drive. Internally, it contains Partition tables, file systems, folders, files, and data, just as if we were working with a physical disk connected to our computer.

It originally emerged from Connectix, until Microsoft bought this technology in 2003. Since then, it has been an integral part of environments such as Microsoft Virtual PC, Hyper-V, and later, within the operating system itself. VHD files in Windows have various applications. These are the most notable:

• Native boot of an operating system, loading a complete environment from a VHD.
• Backup and restore of complete systems or disks.
• Creating test environments software on multiple systems without the need for physical partitions
• Data protection and sharing, making it possible to hide a VHD when we don't use it.
• Virtualization of operating systems, used as a storage unit for virtual machines in Hyper-V.

Available VHD file types

VHD files in Windows allow us to create virtual disks in three different variants, each designed for specific scenarios:

• Fixed-size VHD: It occupies all the space allocated to it from the start. It is faster and more stable for intensive operations.
• Dynamic VHD: It takes up little memory at first, and grows as the data fills up. It saves space, but is slightly slower.
• VHD of differentiation: Functions as a "child copy" of a base disk. Ideal for managing multiple environments with a single base system and storing only changes.

Requirements and considerations before creating a VHD

Before you jump into creating and mounting these virtual disks using VHD files in Windows, it's important to keep in mind some restrictions and technical details:

• You must have administrator permissions to create VHDs.
• They cannot be stored within the Windows root directory. (for example, C:\Windows).
• The minimum size allowed for a VHD is 3 MB.
• The maximum size for standard VHD files it is 2 TB (2040 GiB).
• Can only be created as a basic disk, not dynamic or extended.

How to create and mount a VHD file in Windows step by step

The process may vary slightly depending on the version of Windows. Below we show you the most common way from the Disk manager:

1. Press Win + X and select Disk management.
2. In the top menu, click Action > Create VHD.
3. Select the location and name where the file will be saved.
4. Choose VHD or VHDX format (more on this below).
5. Define the disk size.
6. Choose if you want a type dynamic or fixed size.
7. Click on Accept and wait for the file to be created.

Once created, you'll see a new drive grayed out in the disk console. To get it up and running:

• Right click and select Initialize disk.
• Choose MBR (Master Boot Record) as the boot type.
• Right click on the unallocated space and select New Simple Volume.
• Follow the wizard to assign a letter and format it (usually in NTFS).

What are the differences between VHD and VHDX?

In Windows Server 2012 and Windows 8 onwards, Microsoft introduced a new version of the format: VHDXThis comes with significant improvements, surpassing the advantages of classic VHD files on Windows:

Feature	VHD	VHDX
Maximum capacity	2 TB	64 TB
Compatibility	Windows 7, 8, Server 2008	Windows 8, 10, 11 and Server 2012+ only
Unlimited	Standard	Optimized for large volumes (4KB sectors)
data integrity	Prone to corruption	Integrated failover and metadata
Resizing	Not supported	Allows you to reduce or enlarge hot
Trim/Data Trimming	No	Yes

 

VHDX is more robust, efficient and modern, but if you need compatibility with older versions of Windows or software that doesn't support the new format, using VHD is still valid.

Practical use cases for VHD files

The versatility of VHD files in Windows allows them to be useful in a wide variety of contexts:

• Sharing disk between multiple virtual machines: Just like a USB, you can mount the same VHD on multiple VMs to share data.
• Second operating system: Create a second Windows inside the VHD and configure it as an isolated boot disk from the main one.
• Save private information: You can hide a VHD when not in use, preventing unauthorized access.
• Digital backup: Instead of cloning an entire physical disk, you can save its image as a VHD file.
• Data recovery: Programs like R-Studio allow you to extract files from corrupted or damaged VHDs.

VHD files in Windows are a versatile and powerful solution for virtualization, backup, and data protection. Their ease of management, along with increasingly integrated support within the operating system, makes them a ideal tools for both domestic and professional environments.