[dmoskaluk]

Having run the gamut of glitches and grief since doing the High Sierra upgrade ( and subsequent updates) I was at my wits end with respect to the "Sleep-Wake-Fail" & rebooting , which was occurring 2/3 of the time when the iMac was sleeping. I am resigned to simply waiting until next fall when whatever replaces High Sierra comes out, hopefully all the crash reports are going somewhere ( I send them,- per the on screen request, every time ie more than daily,for at least 2 months) and there will be a fix. However what I've found works very well is s to use the 'Power Saving' settings to tell the hard drive to stay awake all the time ie sleep-NEVER, while selecting 'screen sleep' to any realistic value ( I chose 45 min). As a personal preference I use a screen saver ( stock) from 5 min inactive to the screen timeout at 45 min. I've had it set up this way for a month, and the computer is faster than its ever been ie 'better than new'. ( It's a late 2012 model) Browsers open instantly and mouse and keyboard respond 'lightning fast' for any function. I have never had even mild warmth or heard any fan activity indicating that the HD is in any way stressed. While experimenting with this set up I did try a few times to 'manually' select sleep but I still would get no end of issues ( foggy, slow wake ups plus Bluetooth issues, after any sleep over about 2 hrs, plus the sleep wake failure / reboots being constant) . Am I abusing the hard arrive simply by only sleeping the screen? - since the performance has been 110% of what it was in the years even before the High Sierra issues.... I believe that that many office setups do not use sleep modes and the HD's run 24/ 7 with adaptations to save a bit by simply sleeping the screen. I live in the Caribbean so ambient temperatures are relatively warm ( high 70's at night, mid 80's day and the room where the desk and iMac are located doesn't not have AC but as I said, the entire screen-back remain cool to the touch at all times. I had to dig a bit to see if the HD was solid state, but it's not....

[Golfdriver97]

I do not have much experience with Apple machines, but I will still give this a go:

I have never had even mild warmth

The HDD may still be failing. It is mechanical, and parts will literally wear out.

heard any fan activity indicating that the HD is in any way stressed

The HDD doesn't have a fan. It is basically a small box (if I am looking at the right machine, it's probably a laptop sized HDD) that has several platters that spin like a record on a record player. You might be hearing the platters spinning, but it's not a fan.

Am I abusing the hard arrive simply by only sleeping the screen?

As far as I know, yes. The more an HDD is active, the wear and tear happens. In this case, you are adding wear and tear by having it run all the time.

Is there any way you can check the status or health of the drives? I found a couple articles that show this may be possible.

https://support.apple.com/en-us/HT201257

Check Hard Drive Health of a Mac with Disk Utility

If either of those work, and they give a result of the drive beginning to fail, I would immediately make a backup and begin to consider your options for a replacement or repair.

In all honesty, I would create a backup no matter what. I am fairly certain that this drive is on it's deathbed.

[Quis89]

As long as you're still regularly powering off your machine, you'll be fine. Sleep is helpful because it allows you to use your computer quicker when you come back to it. But if you're experiencing issues with it there's nothing wrong with not allowing your HDD to sleep. Just make sure you're powering your computer down regularly.

[doogald]

The HDD doesn't have a fan. It is basically a small box (if I am looking at the right machine, it's probably a laptop sized HDD) that has several platters that spin like a record on a record player. You might be hearing the platters spinning, but it's not a fan.

FWIW, an iMac with a spinning disk hard disk drive has a heat sensor mounted on the drive itself and calls on the iMac's ventilation fan when the temperature gets too high. So, yes, if the hard disk is stressed, you would probably start hearing fan noise from the iMac, not, as you say, from the disk drive itself.

[dmoskaluk]

OK- no noise whatsoever from anywhere, and as I indicated, the room temperature is 'tropical'. I have not powered down for about a month. ( Last power blackout) either. I did run the onboard disk utility as was thoughtfully suggested, and it came back 'clean as a whistle'...but I'm about to do a back-up to an external device out of 'an abundance of caution' aa they say.....Thanks again for the quick replies....

[Not Quite Right]

How about wiping the HDD and doing a clean install of High Sierra? Then leave all the settings at default for a few days. If the computer still exhibits the unwanted behavior, you can most likely point your finger to a hardware failure ...

[dmoskaluk]

Thanks - will hold off on the 'surgery' for now as I really don't have much to lose by simply using the machine as I have since mid-Feb.....I appreciate the comment though ......

[Golfdriver97]

OK- no noise whatsoever from anywhere, and as I indicated, the room temperature is 'tropical'. I have not powered down for about a month. ( Last power blackout) either. I did run the onboard disk utility as was thoughtfully suggested, and it came back 'clean as a whistle'...but I'm about to do a back-up to an external device out of 'an abundance of caution' aa they say.....Thanks again for the quick replies....

Depending on how much your data changes, you may want to consider making a backup habitual. I would honestly suggest at maximum once per month.

[dmoskaluk]

I will do a back up monthly, to my 'Passport Ultra', and just for peace of mind I downloaded and installed 'TG' ( Temp Guage') Pro from Paddle ( a UK outfit) which will now monitor and read out more temperature related information than I can cope with .....All parameters are very much in the green. Thanks all for the timely input and suggestions....

[dmoskaluk]

I just updated to Mojave - hoping that the problems which were introduced with 'High Sierra' last year, would be remedied. Not so. I like the presentation of Mojave, particularly the Dark mode appearance but when I went to defaults for hard drive sleep etc, and allowed to go to sleep, I had the same issues as early this year. So I've gone to my workaround, simply use Screensaver after 5 min inactive, and screen sleep after 30 min, monitor internal temps carefully and do a monthly backup. Machine is snappy quick and silent at all times.