I’ve found it pretty handy to run a defragmentation in a guest OS before trying to shrink virtual hard drives. Not sure it affects all virtual drives but hyper-

I’ve found it pretty handy to run a defragmentation in a guest OS before trying to shrink virtual hard drives. Not sure it affects all virtual drives but hyper-v vhdx can compact poorly if the data is quite fragmented and it’s often easier to defrag in the guest if the filesystem isn’t something you have drivers for on the host.