How to compress VHDX after creation based on physical disk?

Question

Windows Server

Colleagues, help.
There was a 600 GB physical disk with two equal partitions. Based on it, a virtual disk for Hyper-V was created. The size turned out to be 559 GB (I don’t know why not 600).
Inside VHDX, the first partition (259) was immediately compressed to 50, and the second (300) is not compressed! The disk manager, when commanded to compress, eventually gives out that there is not enough free space . There is a lot of space everywhere (and inside sections too). With the same manager, the partition can be expanded and compressed again, but only up to 300.
When trying to compress a VHDX file using the Hyper-V wizard (Change Virtual Hard Disk Wizard), the wizard writes at the stage of a new size specification that the minimum size is 559 GB.
I tried to increase the VHDX file by 1 GB. Successfully. You can compress again only up to 559 GB.
At the same time, the partitions inside the virtual disk are one for 50, the other for 300, and free 209. And these 209 cannot be freed. Skandisk and defragmentation passed in every possible way.
There are features, but I want to believe that I'm out of my mind and they do not affect:
1. There is quota management
2. There are shares with access by users that admins do not see. But the system sees.
Tell me, please, how to win?

Answer 1

Сначала нужно очистить том sdelete.

@Echo OFF
Echo %COMPUTERNAME%: > run.log
Echo %DATE% %TIME% Clean free space >> run.log
sdelete.exe -C
Echo %DATE% %TIME% Zero free space >> run.log
sdelete.exe -Z
Echo %DATE% %TIME% End>> run.log

И сделать дефрагментацию.