I ran Virtualbox today and nothing happened, as if I had not clicked its icon. There was no error message but I figured it was failing so I ran it from the command line and got the following error:
VirtualBox: Error -610 in supR3HardenedMainInitRuntime! VirtualBox: dlopen("/usr/lib/virtualbox/VBoxRT.so",) failed: <NULL> VirtualBox: Tip! It may help to reinstall VirtualBox.
When I Googled this I found all kinds of ideas, none of which worked. I checked the package versions, there were no version mis-matches. Finally I found an obscure thing that fixed it:
My /usr/lib directory was set to root:staff, mode 775. I had been working on Nixnote, an open source Evernote client, and needed to install some stuff there, so I changed the ownership so I wouldn’t have to sudo to copy new files there.
Well it turns out Virtualbox won’t run unless /usr/lib is root:root. Don’t ask me why, I don’t know and it doesn’t make sense. And Virtualbox doesn’t tell you this, nor is it mentioned in their docs. But setting it back fixed the problem.