I prefer to always manually shut down or put computer to sleep. So far; Unsuccessful settings.

[Hammer Under Glass]

iMac keeps trying to shut down, or go to sleep, with settings of power save and window saver set on never, including unwanted action of iTunes, Numbers and Pages being closed automatically.

Wanted: To only put computer to sleep or shut down manually. I don't want auto shut down/ sleep/ screen saver.

 

[Taz Mangus]

Does the computer restart automatically after it shuts down? Do you see any error message being displayed? Look in the Console app for any crash logs. If there are any see what they say is the reason for the crash.

 

[chscag]

It doesn't sound like a kernel panic or a system crash.

You didn't mention which version of macOS you're using, but check this: (I'm using Catalina 10.15.6)

System Preferences, Security & Privacy. Click on the small lock at the bottom and enter your admin password. When the lock opens, click on the "advanced" button.

Check to see if you have selected "log out after xx minutes of activity".

 

[Hammer Under Glass]

Does the computer restart automatically after it shuts down? Do you see any error message being displayed? Look in the Console app for any crash logs. If there are any see what they say is the reason for the crash.

It doesn't sound like a kernel panic or a system crash.

You didn't mention which version of macOS you're using, but check this: (I'm using Catalina 10.15.6)

System Preferences, Security & Privacy. Click on the small lock at the bottom and enter your admin password. When the lock opens, click on the "advanced" button.

Check to see if you have selected "log out after xx minutes of activity".

I was in the advanced and skimmed right by this. Thank You.
Using Mojave 10.14.6 The same settings you suggested were available.

 

[FarmerBob]

I'm in 10.14.6 and it seems when I over tax the system which I have no idea when and what it takes, I get the "Beach Ball of Death" and am thrown to the User Login window. Which I rarely use. I login and all the apps that were running restart. All apps that have docs that need to be saved before the app can close, are open and the docs are as they were before the "crash". But I haven't had any full out reboot crashes as I have in the past. I have been changing the Sleep, Screen Dim and Screen Saver settings a lot due to running Monitor Calibration and DNS/Internet tests. When I put them back to Screen Saver at 10 minutes; Screen Off at 15 minutes; Sleep at 25 minutes, everything seems to go back to that point and works as it should.

When I do have a major crash or get kicked to the User Login, I run my new best friend "Onyx" that for these latter OSs seems to be the best thing to clean up any mess left behind or fix what may have caused the "issue". After running it things feel more stable and smoother. I have known of Onyx for ages, but this is the first time it's really done anything for me. And it does . . .

 

[Hammer Under Glass]

I'm in 10.14.6 and it seems when I over tax the system which I have no idea when and what it takes, I get the "Beach Ball of Death" and am thrown to the User Login window. Which I rarely use. I login and all the apps that were running restart. All apps that have docs that need to be saved before the app can close, are open and the docs are as they were before the "crash". But I haven't had any full out reboot crashes as I have in the past. I have been changing the Sleep, Screen Dim and Screen Saver settings a lot due to running Monitor Calibration and DNS/Internet tests. When I put them back to Screen Saver at 10 minutes; Screen Off at 15 minutes; Sleep at 25 minutes, everything seems to go back to that point and works as it should.

When I do have a major crash or get kicked to the User Login, I run my new best friend "Onyx" that for these latter OSs seems to be the best thing to clean up any mess left behind or fix what may have caused the "issue". After running it things feel more stable and smoother. I have known of Onyx for ages, but this is the first time it's really done anything for me. And it does . . .

So far, the suggestion by chscag of changing the settings in System Preferences, Security & Privacy, Advanced and setting the log out timing is working. However, I will try Onyx as you suggested, as everything seems slower and funky with my Mojave 10.14.6. I, too, am tired of seeing that beach ball of death even if nothing is actually crashing. Creating and saving PDFs is painful and I can't even download Catalina because something gets interrupted. I have Clean My Mac but can't say I've seen much difference in performance. Looks like OnyX is discontinued for Mojave so will have to install Catalina first somehow. Well, I better stay on topic which I think has been solved. Thanks Again.
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Does the computer restart automatically after it shuts down? Do you see any error message being displayed? Look in the Console app for any crash logs. If there are any see what they say is the reason for the crash.

This really wasn't a crash issue as much as finding the proper settings beyond the usual sleep, screen saver ones. I think this one has been solved but I appreciate you responding.

 

[davidlv]

So far, the suggestion by chscag of changing the settings in System Preferences, Security & Privacy, Advanced and setting the log out timing is working. However, I will try Onyx as you suggested, as everything seems slower and funky with my Mojave 10.14.6. I, too, am tired of seeing that beach ball of death even if nothing is actually crashing. Creating and saving PDFs is painful and I can't even download Catalina because something gets interrupted. I have Clean My Mac but can't say I've seen much difference in performance. Looks like OnyX is discontinued for Mojave so will have to install Catalina first somehow. Well, I better stay on topic which I think has been solved. Thanks Again.
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This really wasn't a crash issue as much as finding the proper settings beyond the usual sleep, screen saver ones. I think this one has been solved but I appreciate you responding.

Onyx is still available for Mojave, https://www.titanium-software.fr/en/onyx.html
Development is stopped, but it works.