Fans have been spinning up and then spinning down recently. I have made some changes including two hardware changes, and I am hesitant to mention it because we will all go there, I have recently added a non Apple SSD to my iMac (I am glad I opened it up - the fan was filled with dust) I have also added a Thunderbolt Ethernet 10G adapter.
To Rule out hardware issues. I have run an Apple Hardware Test and it came back with flying colors:
I reset PRAM, the SMC, rebooted in SAFE mode, and eventually reinstalled macOS.
I then went on to troubleshooting tools (TinkerTool, MacPilot) to remove caches, etc.
Finally, I ran defaults delete com.apple.finder
None of this has had an effect on the messages in the console or the fans random spinning up.
Looking in Console is a dangerous thing to do... since latest boot I have over 4000 messages like this;
cfprefsd Couldn't open parent path due to [2: No such file or directory]
How can the system not know where the defaults are for Finder or not be able to open them.
Looking in Activity Viewer


smartctl. The older Mac’s required additional sensors built into the SATA cable from OWC - I own one. This isn’t the case anymore on the later iMacs. I’m still trying to narrow it down. – John Oct 10 '23 at 07:01