This is a problem I’ve had intermittently in the past. It seems to be vanish with certain versions and then come back with other versions. Almost as if a possible bug keeps getting re introduced.
the issue is that quite often my iMac gets stuck on the loading bar about half way and just stalls there forever or either then switches it’s self off or restarts itself. Then it loads right up. On the occasions it’s stuck I have to hold the power button to switch off. I then press it again and it loads right up in a jiffy. But the issue always comes back. Since latest Catalina update the other week it’s been particularly annoying like this. Before that I cannot remember when it last plagued me. One of the Mojave versions I think. Is anyone going else seeing this happen? I though I solved it last night by unplugging my external hard drive which I always leave connected for time machine back ups. It booted several times just fine but then this evening the problem showed itself once more. So that’s not the issue.
i have one of those annoying fusion hard drives in my Mac (i5). I wondered if that’s on the blink but I ran disk utility checks and got clean bill of health on everything. I’m now thinking it’s a dodgy driver bugging out. Possibly even the Bluetooth causing grief, I have one of those magic keyboards and stock Bluetooth mice that came with the iMac. The only reason I say this is the stuck load seems to just before the mouse cursor is about to appear. And during one successful boot neither connected. I was stuck at the login screen with no input so had to fish out an old wired mouse which gave me control and able to restart the Mac. After which it loaded right up quickly and the magic devices were fine.
i guess I want to see if others have similar experiences? At the moment I’m thinking I cannot do much other than to wait for the next Catalina update gets pushed and hope for better.