On my machine, I had to hold command-R for quite a while, at least 60 seconds.Įventually you will see a screen that gives you a couple of options, including reinstalling or running Disk Utility. Basically, you can turn off the security feature requiring user approval of Kernel Extensions.įirst, boot into Recovery Mode by rebooting and pressing and holding command-R as soon as you see the Apple logo. It isn't a great workaround, security-wise, but it does get you back to the behavior of macOS 10.12.