Import a .ova file

If you have a Virtual Machine (VM) that has a .ova extension here's what to do to use it with Virtualbox

  • Open Virtualbox, then go to file –> Import appliance –> Open appliance and select your .ova file
  • Then click Continue then Import
  • It may take several minutes to import
  • Once it's done just select your machine and click on Show to run it

Shared folder

On Linux: once you ran all the instructions here, a CD-ROM will be mounted on the guest. Then, go to /mnt/ and run the file ./ in a terminal.

Manual method If you want to transfer files between your computer (host) and your Virtual Machine (guest) you'll need a shared folder.

  • Create a folder on your computer that will be your shared folder e.g. /home/user/VM_shared
  • Go to VirtualBox and open the Settings of your VM
  • On the Shared Folders section, click on Add a folder
  • Enter the path to your folder AND give it a different name e.g VBShared.
  • Now, start your VM and create a folder e.g /home/user/Shared_Folder
  • Now you need to edit the file /etc/rc.local and add this above the “exit 0 ” line: mount -t vboxsf -o username=uid, groupname=gid VBShared /home/user/Shared_Folder
    • In order to get username/uid/groupname/gid. Open a terminal:
      • Get username –> whoami. Get groupname –> groups (uid and gid respectively) to assign the permissions to the Shared folder
      • gid: getent group groupname (e.g. groupename = NeuroPoly, the command will give NeuroPoly:x:1000 where the 3rd argument is the gid)
      • uid: id -u username
    • For admin rights use sudo vi /etc/rc.local. Or su root. Then vi /etc/rc.local You need the admin password.
  • Now reboot your VM.
  • Make the change permanent: Go to VirtualBox–>settings–>foldershared–>double click–>'Make Permanent' option

If that didn't work it could be because the VBoxGuestAdditions are not installed on your VM. If so, follow those next step :

  • In the Storage section of Settings of your VM add the VBoxGuestAdditions.iso file that you'll find in ( C:\Program Files\Oracle\VirtualBox for Windows or /Applications/ for Mac )
  • In your VM open a terminal and run (for Linux-based VM e.g. Linux,Debian,Ubuntu):
  • cd /media/cdrom
  • sudo bash
  • Reboot your VM

Create a Virtual Machine (VM) with Debian

To create a Virtual Machine with Debian, you can follow this excellent tutorial:


Don't give to your VM more than the half of your system RAM. You need to keep memory for your own system.

Reduce the size of the VM

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
With a Windows Guest, download SDelete and run this:
sdelete –z

Shutdown the guest VM

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:

Install guest additions

Ubuntu 14.04

sudo apt-get update
sudo apt-get install virtualbox-guest-additions-iso

Once installed, click on Devices > Insert Guest Additions CD Image…, then reload VM.