freezing on shutdown: iMac 2017 27 inch

[Wyatt82]

Hi,
So my iMac is failing to shut down properly when I hit the apple shut down command. What happens is the screen goes dark I get the spinning gear wheel and it spins perpetually. I can feel what I suspect is the hard drive/fan (it's a 2TB fusion) doing something but ultimately after 10+ mins I decide to power off. The computer is 4 days old in my possession (bought as a returb from the apple store). I have put 32gb of OWC ram in it. Here is what I have done to solve:

1. Reset SMC and NVRAM.
2. Cleared cache (using disk aid app purchased from App Store).

One thing I would say is that when I turn on the computer and then try to shut down straight away the computer does so without problem. I suspect some process is initiating and then ultimately frustrating attempts to shut the computer down after 30 mins or so of typical use (iTunes, mail, safari etc). I am careful to have all apps closed before attempting to shut down so I ensure no processes are running but I can't see or understand what is happening. Are there terminal scripts I can see to understand what is going on? Hope some of you guys can help.

 

[chscag]

Have you checked the logs to see what might be happening? And of course you have 14 days to return the machine if something is not right with it. You might want to contact Apple and ask them for assistance. Apple Refurbs are covered with the same warranty as new machines.

 

[JoeInMilwaukee]

Try removing the OWC RAM and put the RAM that it came with back in.

 

[Wyatt82]

Thanks Joe I'll try the memory. I called Apple last night and they advised to re-install the OS too.

 

[JoeInMilwaukee]

One other thing to try is running Apple Hardware Test (hold down the 'D' key at powerup and allow the test to load via the Internet, then run the Extended Test) with the OWC memory installed. This can sometimes detect RAM problems.

 

[xgman]

I have similar issues with a couple imacs. To the best I can tell it seems to relate to either things connected (audio devices, ext storage) or certain things that are not quite unloaded at shutdown. Doesn't happen every time so hard to pinpoint. Something is probably loading along the way during your use and then interfering with shutdown. There are some shut down cache clearing things I have googled that do seem to help somewhat, but I still get the hangs pretty often. better with the latest couple betas, or at least I think. I don't think it is hardware. You should note the time and look at the console app system log entry to see what events surround the shutdown point. It sometimes shows hanging things but not always. (also might keep activity monitor app open and sort by cpu use and note anything unusual there as you use the mac) Personally I think it may be related to TB or even usb connected drives or audio interfaces or both. (also make sure it updates to the latest osx version available)

by the way, apple's answer to everything is reinstall and start over. that might help till you load your apps back up and start using the mac normally again. So don't be surprised if it rears up again.

 

[Wyatt82]

Thanks everyone I took it back to the Apple store at Bayshore in Milwaukee. They did an MRI and it came back fine so they did a fresh install and all seems to be well now