I have gone through the article posted in https://www.linuxbabe.com/virtualbox/how-to-install-virtualbox-guest-additions-on-elementary-os-2
I followed the advises and when proceeded for select Devices > Insert Guest Additions CD image . I found Virtual Box error message - “Unable to insert the virtual optical disk /usr/share/virtualbox/VBoxGuestAdditions.iso into the machine ELEMENTARY.”
Therefore, I couldn’t proceed further. I would like to know as to how I clear the deadlock.