If you’re using Hyper-V, and you have a dynamic virtual hard disk (VHDX), then when you delete files from it, the file size won’t shrink automatically.
A great, quick way of getting things downsized is here: https://fiddley.wordpress.com/2014/01/27/dynamically-expanding-vhd-not-compacting-in-hyper-v/
Run an administrative command prompt
Type “Diskpart” (No Quotes)
Type the following commands:
select vdisk File=”I:\path\to\your.vhd”
attach vdisk readonly