Nice article. I had a strange situation where although the ‘Allow’ button was shown, I couldn’t click on it. The install failed even after running `sudo spctl — master-disable`. Eventually I followed the advice here https://apple.stackexchange.com/questions/305638/virtualbox-5-2-wont-install-on-mac-os-10-13/325769#325769 to allow tabbing between all fields, then I was able to tab to the ‘Allow’ button and press Space to activate it. No idea why it wouldn’t let me click the button (I tried using the Trackpad rather than the mouse as suggested elsewhere). Hope this helps someone!