Unregister a virtual machine.
The VBoxManage unregistervm command unregisters a virtual machine (VM).
uuid|vmnameSpecifies the name or Universally Unique Identifier (UUID) of the VM.
--delete
Deletes the following files related to the VM automatically:
All hard disk image files, including differencing files.
All saved state files that the machine created, including one for each snapshot.
XML VM machine definition file and its backups.
VM log files.
The empty directory associated with the unregistered VM.
--delete-all
Deletes the files described in the --delete option,
as well as all DVDs and Floppy disks located in the VM folder and
attached only to this VM.