Virtual hard-drives used by virtual systems running under Hyper-V on Windows 8 Pro (or later) can very quickly become extremely huge in size. Thankfully there is a nice and easy procedure that I always use to minimize and compact them, which presents as following:
- Turn on the system, that is going to be optimized and log in.
- Clean the trash bins, clean `temp` folders and remove all other unneeded stuff from the system drive (like: old system restore points), turn off hibernation and finally turn off or reduce the size of paging file.
- Defrag if necessary (do it even x3 times, if using Windows XP as guest OS).
- *critical* – clean the reclaimed space using sdelete.exe utility from SysInternals (available here).
- Turn off the guest system.
- Run the Hyper-V management console and optimize the VHD size from there.
Done. Good job!