Today, I was upgrading my Ubuntu virtual machine, when I got the following error:
My suspect fell on the very small size of my dedicated ram: just 768 MB.
I resized my virtualmachine, and then with gparted I resized the swap memory.
everything was fine without further problems.
However, I suggest you to increase the amount of dedicated ram from the virtualbox settings. That might be enough, and you probably don’t need anything more to upgrade your linux virtualbox system.