iMac freezes after a long wait during startup. Won't boot in Safe Mode.
I think my iMac is a late 2015 5K, 27" screen. It freezes after a long wait and the progress bar finishes. It won't boot in Safe Mode. The progress bar freezes halfway through booting with the spinning wheel freezing too. MacOS Recovery test finds nothing wrong.
I'm stumped at this point. Any suggestions are welcomed. BTW, I'm using High Sierra MacOS.