13 Jan
2016
13 Jan
'16
10:57 a.m.
Do you have the VirtualBox Extension pack installed which matches your version of Virtualbox exactly?
I installed an extension pack at the same time as when I installed Virtualbox (a few months ago). I suppose it's possible that one of the routine Ubuntu updates also installed a newer version of Virtualbox, which would have caused a mismatch. Will have to check that...