This is a bit awkward problem I'm having right now. **not trying to boot from external HDD** On my iMac, (probably late 2012) I usually work with 3~4 external HDDs attached. And when I do a reboot, it simply doesn't boot up and stays in the grey screen until I remove all the external HDDs. Not only that, I can't even type passwords in as I login, so pretty much either I end up with grey screen or login screen where I can't type unless I remove HDDs. (just on the side note, both HDDs and keyboard is attached via USB) Another odd problem is that I can't use my mice, Logitech MX Master, on the login screen. I can only maneuver with the Apple bluetooth trackpad. Has anyone encountered these sort of issues? What was your solution other than disconnecting all the drives?