Virtualbox Disk Reduce or Disk Compact Rumi, February 9, 2016February 9, 2016 You have to do the following steps: 1. Run defrag in the guest (Windows only) Nullify free space: With a Linux Guest run this: sudo dd if=/dev/zero of=/bigemptyfile bs=4096k sudo rm -rf /bigemptyfile Or: telinit 1 mount -o remount,ro /dev/sda1 zerofree -v /dev/sda1 Or sudo apt-get install secure-delete sfill -f -z -l -l -I -v / With a Windows Guest, download SDelete from Sysinternals and run this: sdelete –z 2. Shutdown the guest VM 3. Now run VBoxManage’s modifyhd command with the –compact option: With a Linux Host run this: vboxmanage modifyhd /path/to/thedisk.vdi --compact With a Windows Host run this: VBoxManage.exe modifyhd c:\path\to\thedisk.vdi --compact With a Mac Host run this: VBoxManage modifyhd /path/to/thedisk.vdi --compact This reduces the vdi size. Src: http://superuser.com/questions/529149/how-to-compact-virtualboxs-vdi-file-size http://marianposaceanu.com/articles/how-to-reduce-the-size-of-your-vms Virtualbox virtualbox