How to Compact a VHD or VHDX File using PowerShell

Compacting the virtual hard disk files can make their size significantly smaller, depending on how much white space they have.

The older (or more used) the drive, the better your chances are for massive space gain.

Compact VHD/VHDX

1. Open an elevated PowerShell window (Win + X keys, then press A).

2. Mount the VMD or VHDX files as read-only. This is important to do, otherwise the new command might fail. Then use the Optimize-VHD cmdlet (even with vhdx files) and dismount the file when finished.

# Mount temporarily the Example.vhdx file as read-only
Mount-VHD -Path "D:\VMs\Virtual Hard Disks\Example.vhdx" -ReadOnly

# Compact the virtual drive
Optimize-VHD -Path "D:\VMs\Virtual Hard Disks\Example.vhdx" -Mode Full

# Dismount the vhdx file
Dismount-VHD -Path "D:\VMs\Virtual Hard Disks\Example.vhdx"