I recently downloaded and processed some large files on Windows Subsystem for Linux (WSL) on Windows 10. Once I was done with the files, I deleted them from my Ubuntu installation, but the VHD file was still taking up the same amount of space as it was before I deleted the files.

It turns out that Windows and WSL does not automatically shrink the VHD file if you delete files - it just automatically expands it as you use more space in WSL.

How to shrink the VHD file

Locate the VHD file in your user directory of Windows. For me, this was: “C:\Users\Nick Plunkett\AppData\Local\Packages\CanonicalGroupLimited.Ubuntu_79rhkp1fndgsc\LocalState\ext4.vhdx”

In order to reclaim the disk space that is no longer in use in WSL, open a powershell window and run the following commands: