Claim VirtualBox HD Empty Space File Size

If You often Use VirtualBox to do your work, after sometime you will see the Disk (VDI) File Size increasing so Big. Even after you Delete many Files inside Guest OS, it still keep the size larger.

You can do following steps to Reduce it:
1. Run Defrag in the Guest (Windows)
2. Nullify free space:
With Linux guest run this:

sudo dd if=/dev/zero of=/bigemptyfile bs=4096k
sudo rm -rf /bigemptyfile

With Windows guest, download SysinternalsSuite then run this:

sdelete –z

3. After that Shutdown the guest VM
4. Run VBoxManage's compact command

VBoxManage.exe modifyhd thedisk.vdi --compact

All these Step will Reduce your VirtualBox HD. Compare It. :D