I have installed ubuntu 14.04 on oracle virtual machine and right after that I switched to the full screen mode be by installing the Guest Additions with no problem.
But, as I let the system update itself automatically, I have been again switched to small screen. Going to ¨Devices¨ menu I have ¨Insert Guest Additions CD image¨ I receive the following message:
Unable to insert virtual optical disk
/usr/share/virtualbox/VBoxGuestAdditions.iso into the machine Ubuntu_linux
How can I solve this problem?