Apparently I purchased the blow 1TB SSD back on May 14 because the price was good, and my venerable T460 was otherwise running out of space, and I figured I was going to have to duplicate my old iTunes library for connection with my iPhone. I also had a hankering to play some cricket games on Steam.

I therefore set up a Windows 10 VDI for us in VirtualBox with iTunes, Steam and a few other essentials: git, Powershell, VSCode. The games I had in mind would not work on so old a machine, and I found alternate arrangements for music management, BUT the initial 100GB allocated to the VM seems to have grown to over 140GB… a bit pans consideredin there’s no data in the damned thing.

Let’s compress it!

Actually, starting with the easy bit. The command is simply VBoxManage modifymedium "~/VirtualBox\ VMs/win-10-pro/win-10-pro.vdi" --compact but there was not much compression going on… something on the Windows end.

01 Disk Cleanup

Windows keeps a ton of old updates, temp files and general crud that accumulating over time.

• Search for “Disk Clean-up”. Run it.

02 Compact.exe

Compress WIndows system binaries

• Run Compact.exe /CompactOS:always from cmd.exe/Powershell (“Run as Administrator”)

03 Disable hibernate/suspend to disk

• Run powercfg /h off from cmd.exe/Powershell (“Run as Administrator”). VirtualBox has its own suspend functionality anyway.

04 Sdelete.exe

https://docs.microsoft.com/en-gb/sysinternals/downloads/sdelete

SDelete (Secure Delete) is such an application. You can use SDelete both to securely delete existing files, as well as to securely erase any file data that exists in the unallocated portions of a disk (including files that you have already deleted or encrypted).

We’re gonna use this to write in a wrote bunch of zeros, which can be easily compressed, as opposed the the

• Run sdelete.exe c:\ -z from cmd.exe/Powershell (“Run as Administrator”).

05 Compress the VM

• Run VBoxManage modifymedium "~/VirtualBox\ VMs/win-10-pro/win-10-pro.vdi" --compact

And Lo!