Cloning requires changing the UUID to avoid conflicts befor VirtualBox will allow registering it. Copy img or vdi file to a new location/name Execute VBoxManager internalcommands sethduuid <newName.img|.vdi> In VirtualBox GUI create a new machine When its time to create a new or select existing Virtual Hard Disk select use existing. Click on the folder and then click the Add icon Select the new img or vdi file that you changed the uuid above Complete configuring the machine as typical.