Careful. If you remove the wrong drive, your VM will no longer boot. If you are worried, clone the VM first before proceeding.

# Power off the VM.
# <code>VirtualBox</code> &rarr; <code>click a VM</code> &rarr; <code>Settings</code> &rarr; <code>Storage</code> &rarr; <code>click on DVD device add symbol</code> &rarr; <code>click Leave Empty</code> &rarr; <code>click OK</code>
# Usual way to add DVD's to VirtualBox VMs can now be used such as <code>VirtualBox</code> &rarr; <code>click a VM</code> &rarr; <code>click on [Optical Drive]</code>