Anyone else have a 17 imac that occasionally gets stuck on the final dark grey screen and doesn't go black unless you push the button down? I have tried all the suggested fixes repeatedly (smc,pram,startup items,etc) and because the issue is intermittent it is very hard to pin down. I was just wondering if anyone else has this issue on occasion?
I had the issue until I ejected my external drive. For some reason it was hanging the system up and it wouldn't shut down or restart. If you don't have an external, try logging out first then shut down or restart. It worked for me.
"I have a TB3 drives enclosure but this didn't start happening until the last HS updates." Then.... it sounds like a software problem (OS)... not "the hardware".
Well did you even try my suggestion? My computer came with HS so it can very well me software hanging the system up.
I've had this problem on and off for years over two iMacs (which means it might be some hardware or software element I've used with both of them). You're right, it's very hard to pin down, but over several major operating systems I think it's happened least with High Sierra for me.
I tried it once and it was fine, but this could go 10 shut downs and then start again. I have a feeling it has to do with either my TB3 drives or TB2 UAD audio interface updated drivers (coincidence maybe) but it is really impossible to troubleshoot in a logical sense since it doesn't always hang. I do not think it is software because I control and monitor what is allowed to start up pretty well, but could be driver related to the audio I suppose. I'll keep trying the eject method to see if it ever happens after ejecting the drives. This is such a windows pc 1990's thing though. Whenever it happens I have a horrible sense of dread.