It doesn't matter which of any of the mentioned key combinations I hold down, my 27" iMac (Retina 5k 2019) boots as normal. What gives?
I've tried numerous times to "reinstall MacOS" by rebooting. As soon as I press Enter to confirm "Restart" I hold down Option-Command-R. I have also tried just Command-R. In every case, the computer (Retina 5k 2019 27" iMac) boots as normal to my User login. Something isn't right about that, right?
iMac, macOS 10.12