Lately, macOS updates break VirtualBox with "Kernel driver not installed (rc=-1908)" error. Not only is this highly annoying and oh-so-expected, but a reasonable solution (that does not involve reboots into Recovery mode, endless uninstalls and reinstalls, etc.) to this error is not terribly easy to find. After some poking around, I came across this and it worked:
1) restart the Mac
2) % sudo /Library/Application\ Support/VirtualBox/LaunchDaemons/VirtualBoxStartup.sh restart
VirtualBox runs fine again. Whew!
Thank you to https://stackoverflow.com/questions/13670176/virtualbox-error-kernel-driver-not-installedrc-1908 for the answer.
P.S. Why am I still bothering with VirtualBox???
