iMac Intel runnning 15.0.1 shut down instead of sleeping

Thank you, James Brickley. I will do that tonight.

Last night, as a test, I enabled "Prevent automatic sleeping when the display is off" in "System settings/Energy Saver". It was disastrous. Sure enough, the screen was on, and the machine was pretty hot this morning, but I was not able to do anything with it. The trackpad only flashed a cursor for less than 1 second every so often, (the very large cursor version) But I had no control of it. There was a very small login icon and password window at the bottom of the screen, but I could not select it. Besides, the keyboard seems to be unresponsive, although I could not be sure. Eventually, I shut the machine down, waited, disconnected it, waited, reconnected it, and restarted it.

After a little while the login scree,n appeared, but the trackpad and keyboard were on for only a few seconds every once in a while. After several tries, I managed to type my password and booting resumed and completed successfully. (not very fast, but not superslow either). Now the machine functions normally, the fan has stopped, although the back around the exhaust slots is still quite warm to the touch.

As I said, I will get the details overnight and share them. I am running similar tests on my Macbook Pro, which is developing similar symptoms. I have used pmset in the past. The sheer volume of data and difficulty reading it just reminds of core dumps on the IBM mainframes in the 60's and early 70's.

Here is the first output:

System-wide power settings:

Currently in use:

autorestart 1

Sleep On Power Button 1

halfdim 1

hibernatefile /var/vm/sleepimage

proximitywake 1

powernap 1

gpuswitch 2

networkoversleep 0

disksleep 10

sleep 1 (sleep prevented by sharingd, bluetoothd)

hibernatemode 0

ttyskeepawake 1

displaysleep 20

tcpkeepalive 1

womp 1

The pmset -g log | pbcopy could not be uploaded, even with the extra text feature. I captured the log output into a text file and found that the shutdowns of the past few days were code -108 (except for the button shutdowns, of course). So I shutdown the machine, disconnected everything and zapped PRAM/NVRAM. The reboot was much faster, which maybe a good sign. I'll go back to my preferred configuration, and keep my fingers crossed. If you wish to see the log file I can make it available by Dropbox or iCloud email.

In the process I discovered that my TM disc (4TB SSD) got fried as of August 28 (about 6 weeks). It won't be recognized by iMac not MacBook. I will also prepare a new disc. Not worried yet, as my important stuff is backed up using Crashplan, but I like the duplication. :-). I'll report tomorrow

Yes, The first "pbcopy" output text file was 4,557 pages long, a bit long for messaging!

The machine turned itself off again last night. I'll run "pmset" again and will save only the output for the past 24 hours.

I discovered "EtrecheckPro" 2 or 3 weeks ago from the forum in a different conversation. I downloaded it and ran it at the time, and tried to follow the suggestions, but only half-heartedly, as I was looking for a "standard" fix. I'll try again, since this looks like an issue where the usual basic resets do not suffice, and will post the report as well. I can tell that it will require a bit of patience, and maybe a lot of time. ;-)

I tried to use the Console, but you are right that there is a lot of noise. There may be flags that streamline the output, but the man pages are a bit painful to digest. Besides I am (actually used to be, in my youth) more comfortable with csh than with bash or zsh. However, I will send a snippet that seems to occupy the system for a very long time.

BTW, zapping the PRAM/NVPRAM did not resolve the issue. "Diskutil FirstAid" gave a pass to the iMAC SSD storage, and my TM disk is still deader than a doornail. It spins but is not recognized by either machine. I disconnected it. (It is actually a spinning disk and not an SSD, but LaCie uses almost the same enclosure for both devices.)

Stay tuned, and thank you!

Here is a sequence that repeats for hours in the system log (console) I will see whether this goes away after disconnecting the TM disk.

Oct 14 14:42:41 gallix syslogd[157]: ASL Sender Statistics

Oct 14 14:43:15 gallix AMPDeviceDiscoveryAgent[1020]: Entered:_AMMuxedDeviceDisconnected, mux-device:192

Oct 14 14:43:15 gallix AMPDeviceDiscoveryAgent[1020]: Entered:__thr_AMMuxedDeviceDisconnected, mux-device:192

Oct 14 14:44:17 gallix AMPDeviceDiscoveryAgent[1020]: Entered:_AMMuxedDeviceDisconnected, mux-device:193

Oct 14 14:44:17 gallix AMPDeviceDiscoveryAgent[1020]: Entered:__thr_AMMuxedDeviceDisconnected, mux-device:193

Oct 14 14:44:47 gallix AMPDeviceDiscoveryAgent[1020]: Entered:_AMMuxedDeviceDisconnected, mux-device:194

Oct 14 14:44:47 gallix AMPDeviceDiscoveryAgent[1020]: Entered:__thr_AMMuxedDeviceDisconnected, mux-device:194

Oct 14 14:47:05 gallix AMPDeviceDiscoveryAgent[1020]: Entered:_AMMuxedDeviceDisconnected, mux-device:195

Oct 14 14:47:05 gallix AMPDeviceDiscoveryAgent[1020]: Entered:__thr_AMMuxedDeviceDisconnected, mux-device:195

Oct 14 14:47:14 gallix AMPDeviceDiscoveryAgent[1020]: Entered:_AMMuxedDeviceDisconnected, mux-device:196

Oct 14 14:47:14 gallix AMPDeviceDiscoveryAgent[1020]: Entered:__thr_AMMuxedDeviceDisconnected, mux-device:196

Oct 14 14:48:38 gallix AMPDeviceDiscoveryAgent[1020]: Entered:_AMMuxedDeviceDisconnected, mux-device:197

Oct 14 14:48:38 gallix AMPDeviceDiscoveryAgent[1020]: Entered:__thr_AMMuxedDeviceDisconnected, mux-device:197

Oct 14 14:49:22 gallix AMPDeviceDiscoveryAgent[1020]: Entered:_AMMuxedDeviceDisconnected, mux-device:198

Oct 14 14:49:22 gallix AMPDeviceDiscoveryAgent[1020]: Entered:__thr_AMMuxedDeviceDisconnected, mux-device:198

Oct 14 14:49:54 gallix AMPDeviceDiscoveryAgent[1020]: Entered:_AMMuxedDeviceDisconnected, mux-device:199

Oct 14 14:49:54 gallix AMPDeviceDiscoveryAgent[1020]: Entered:__thr_AMMuxedDeviceDisconnected, mux-device:199

Oct 14 14:52:20 gallix AMPDeviceDiscoveryAgent[1020]: Entered:_AMMuxedDeviceDisconnected, mux-device:201

Oct 14 14:52:20 gallix AMPDeviceDiscoveryAgent[1020]: Entered:__thr_AMMuxedDeviceDisconnected, mux-device:201

Oct 14 14:53:28 gallix AMPDeviceDiscoveryAgent[1020]: Entered:_AMMuxedDeviceDisconnected, mux-device:200

Oct 14 14:53:28 gallix AMPDeviceDiscoveryAgent[1020]: Entered:__thr_AMMuxedDeviceDisconnected, mux-device:200

Oct 14 14:53:28 gallix syslogd[157]: ASL Sender Statistics

I have not forgotten! I disconnected a 2TB USBC SSD to move data to my laptop, and did not reconnect it and the next morning, the iMac woke up from sleep without any trouble. I reconnected the SSD to it, and am waiting to see if the issue comes back! I will run EtrecheckPro and study the report to see if this external disk which has not caused any problem in well over 2 years since I installed it, is conceivably a new cause with Sequoia.

Thanks James!

Good pieces of advice, Thanks. Will try them / use them both. Bernard

EtrecheckPro report posted below:

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EtreCheckPro is frequently recommended on internet discussion forums such as the Apple Support Community. The Apple Support Community, although hosted by Apple, Inc. is a public internet discussion forum like any other. The people providing technical support on the Apple Support Community are usually not Apple, Inc. employees. They are other Apple, Inc. customers like yourself. Etresoft, Inc. cannot guarantee the accuracy of any suggestions you may receive on an internet discussion forum or web site. Please review the Apple Support Community’s Terms of Use Agreement before posting an EtreCheck report on the Apple Support Community. Double-check your report for any personal information.

The Power User package, available as an in-app purchase, provides access to solutions for your reports using our diagnostic engine. You can always contact Apple Support directly or an Apple Authorized Service Provider. They can provide one-on-one assistance either in-person or via internet screen-sharing.

I am growing aware that all the LaCie external disks that I bought in 2020, misreading the label, are in fact spinning hard drives in almost exactly the same enclosures. No wonder they were affordable. Live and learn! Anyway I can use them as long as they don't crash. I find the interface to this discussion to be squirrely, jumping to unexpected places if I hit the wrong key. So some posts are out of order! :-(.

That is correct. That department is being re-organized. In any case, it is self-managed by me, except for the Crash Plan part. About once or twice a year, I ask them to help. The reason I posted that question was to find out whether anyone had encountered the same symptoms, and whether there was a simple procedure to follow. Having said that, The misbehavior seems to have magically evaporated (more or less). I got a new storage for TM that seems to work fine. I reformatted the other (data) external disk to APFS, and the Macs thanked me. I will go through all the apps and put those that have not been used in a long time out of their misery, or in cold storage.

I am keeping an eye on misbehavior. I am pretty sure that my earlier suspicion that the 2 TB data storage was the issue was ill-founded. The disk is back online, and the problem has not recurred. FM! as an old Navy colleague would have said!

Thanks again for your help and advice. Don't close the issue just yet, as it has only been 2.5 days without trouble. If I am in the clear for a week or so, I'll let you know! Bernard

OK, I paused it using

pkill SIGSTOP AMPDeviceDiscoveryAgent

I am pretty sure this was my iPhone just sitting there, disconnected