VHD vs VHDX in Hyper-V: Differences and How to Work With Them

VHD and VHDX are the virtual hard disk formats Hyper-V uses to store the full contents of a virtual machine's disk, including operating systems, partitions, and data. They do the same basic job but differ a lot in capacity, resilience, and features.

Updated September 2026 · Mr.PlanB

Hyper-V Windows Server Storage

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Overview

VHD is the older format and works with earlier Windows Server versions. Its maximum disk size is 2 TB, and it has no support for features such as live resizing, better data alignment, or trimming. Its logical sector size is 512 bytes, and it does little to protect against data corruption.

VHDX arrived with Windows Server 2012. It raises the maximum virtual disk size to 64 TB and uses a 4 KB logical sector size, which aligns better with modern storage systems. It is also more reliable because it tracks metadata updates, which lowers the risk of corruption after an unexpected power loss. VHDX supports live resizing and trimming too, so it suits dynamic production environments better.

Administrators can convert between VHD and VHDX in Hyper-V Manager or PowerShell, but only while the disk is offline. Be careful when snapshots or differencing disks are involved, because a bad conversion can break the disk chain. VHDX disks can also be resized, mounted, merged, or moved between controllers with the built-in management tools.

As a rule, use VHD when you need compatibility with older systems and VHDX for newer deployments that need to scale, perform well, and protect data better.

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