VHD vs VHDX: What’s the Difference and How to Choose?

VHD vs VHDX: What's the difference?

VHD and VHDX are Microsoft virtual hard disk formats used with Virtual Machines (VMs). They store the operating system, applications, and data like a physical drive. VHDX is the newer version, offering better performance, larger storage, and improved data protection. The table below summarizes their key differences, advantages, and disadvantages.

Feature	VHD	VHDX
Maximum Storage	2 TB	64 TB
Supported OS	Windows Server 2008–2012 R2, Windows 7+	Windows Server 2012+, Windows 8+
Logical Sector Size	512 bytes	4 KB
Resizing	Not supported	Supported
Data Protection	Limited	Tracks metadata, prevents corruption
Trimming & Alignment	Not supported	Supported, improved alignment
File Type	Fixed or dynamic	Fixed, dynamic, or differencing
Compatibility	Windows, Citrix, Oracle	Windows only
Pros	- Compatible with older Windows - Easy backup & restore - Supports multiple OS - Undo changes via differencing disks	- Larger storage capacity - Improved performance - Tracks metadata for protection - Supports trimming & alignment - Better for modern hardware
Cons	- Max 2 TB - No live resizing - Limited partition options (NTFS/FAT32)	- Supported on fewer OS versions - Partition options limited (NTFS/exFAT) - May require Hyper-V to open

You can convert between VHD and VHDX formats using Hyper-V Manager or PowerShell. The conversion process is offline, and it’s important to avoid converting if the VHD has snapshots, serves as a parent to differencing disks, or is part of a Hyper-V Replica setup.

For common operations, you can mount a VHD or VHDX file to access its contents, and when finished, dismount it to safely disconnect the virtual disk from your system. Resizing is also supported for VHDX files, allowing you to expand or shrink the virtual disk as needed. Additionally, if you are working with differencing disks, you can merge changes from the child disk into the parent disk to consolidate data, but this operation is offline and will remove the differencing disk once completed.

How to create VHD or VHDX and easily manage it?

Virtual Hard Disks (VHDs) and their advanced version, VHDX, are disk image files that function like real hard drives on a Windows PC. They allow you to store the operating system, applications, and data in a safe, flexible way. VHDs are commonly used to run virtual machines, back up important files, or test software without affecting the main system. Managing these virtual disks efficiently requires the right tool, and AOMEI Partition Assistant provides a simple solution.

With its built-in “Virtual Disk” feature, AOMEI Partition Assistant lets you create, attach, and detach VHD or VHDX files with just a few clicks. You can choose the disk format and type, specify the size and location, and even use dynamically expanding disks that grow as data is added. Once created, the virtual disk can be initialized, partitioned, and assigned a drive letter, making it ready for use like any other physical disk.

Attaching existing virtual disks is just as easy, and you can safely detach them when they are no longer needed. Thanks to AOMEI Partition Assistant, managing virtual disks on Windows becomes fast, reliable, and intuitive, whether you are backing up VHD file, testing software, or running virtual machines.

1. How to Create VHD

If you want to create a VHD, you can follow the steps below:

Step 1. Click the tab "Virtual Disk", you will see 3 options available for VHDs: create VHD, attach VHD, and detach VHD. Select the "Create VHD" option after clicking the "Virtual Disk" tab.

Step 2. You can specify the virtual disk location and size. 

Optionally, you can click the "Advanced" option to set the virtual hard disk format and type. (By default, the VHDX format and the Dynamically expanding type are checked.)

Virtual hard disk format: VHD and VHDX are supported. 

For VHD, it supports virtual disks up to 2040GB in size.

For VHDX, it supports virtual disks larger than 2040GB in size. (Up to 64TB) This format is not supported in operating systems earlier than Windows 8 or Windows Server 2012.

Virtual hard disk format: Fixed size and Dynamically expanding are supported.

For fixed size, the virtual hard disk file will be allocated its maximum size when it is created. So it will take much longer to create.

For Dynamically expanding, the virtual hard disk file will grow to its maximum size as data is written to it. (Recommended)

Click "Browse" to select a location to create the VHD. Please enter a file name for the virtual disk and click "Save".

Step 3. Once the virtual disk location and size are set up, you can click "OK" to start creating the VHD.

Step 4. After the reload process is finished, you will see that the VHD has been created successfully. It will be attached automatically.

You can also view the VHD in Windows Disk Management.

The created VHD will be uninitialized so it is empty without any data or file system. To make it useful, you need to initialize the disk, create a partition, and assign a drive letter.

You can initialize the drive in Partition Assistant.

Or, initialize it in Windows Disk Management.

Then, you can create a partition and assign a drive letter for the partition. Finally, you can use the VHD normally. 

2. How to Attach VHD

A VHD is a container file that holds a virtual disk image. Until it is attached, Windows sees it only as a regular file. Once attached, Windows mounts it as a virtual disk, assigns a drive letter, and allows access to its file system. You can only perform disk operations, such as cloning VHD to HDD, checking for corruption or errors, or resizing partitions, after attaching it. Detaching the VHD safely removes it from the system without deleting the file.

Step 1. Select the "Attach VHD" option after clicking the"Virtual Disk" tab.

Step 2. Click "Browse" to locate the location where the .vhd or .vhdx file is saved. Select the .vhd or .vhdx file you want to attach and click "Open" to attach it.

Step 3. Once the virtual file is selected, you can click "OK" to start attaching the VHD.

Step 4. Once the process is finished, you will see that the VHD is attached successfully.

3. How to Detach VHD

If the VHD is not necessary, you can remove it by detaching the VHD.

Step 1. You can right-click the attached VHD in Partition Assistant and select the "Detach VHD" option to detach it.

Or, you can select the "Detach VHD" option after clicking the"Virtual Disk" tab.

Step 2. You can select and deselect the virtual disk(s) and click the "Detach" button to start detaching the VHD(s).

Step 3. Once the process is finished, you will see that the VHD(s) has been removed successfully.

Conclusion

Choosing between VHD and VHDX depends on your virtual disk needs. VHDX provides higher storage, improved performance, and better data protection, while VHD remains compatible with older Windows systems. Using AOMEI Partition Assistant makes it easy to create, attach, and manage these virtual disks. Whether you are running virtual machines, backing up files, or testing software, picking the right format and management tool ensures your virtual disks are safe, efficient, and easy to use. If you are a Windows Server user, please choose