MacOS – Transmission aborts automated shut down.

As you have seen, all Apple products actually run even when you power them off. On iOS, the battery keeps time and on Macs, the SMC is responsible for knowing when the power button is pressed and if the Mac should start itself up due to a scheduled wake or power on being saved in the NVRAM.

If you called for service, Apple would likely focus on several things:

1. Have you checked that the firmware and software is up to date.
2. Does this happen every single time, or is it an occasional thing.
3. Have you disconnected everything (including the mouse and keyboard) and tested to see if it's in any way related to a peripheral.

Assuming you can reproduce this at will (it happens every time), you would probably take steps to reset the SMC to ensure it's getting proper readings from the temperature sensors.

• Intel-based Macs: Resetting the System Management Controller (SMC)

If after spending the 10 minutes it would take to read through each and every step (I feel it's important to perform the steps in order - even if they seem unrelated or unnecessary), I would expect them to want to run diagnostics to physically open the Mac to check the sensors and wiring. Your symptoms sure sounds like the SMC either is stuck in some loop and not reading the temp sensors. Failure to control the fans properly could also be a hardware issue where the SMC is receiving a signal where the correct action is to keep the fans not only spinning, but spinning at an elevated level.

I have solved this indirectly in the past several times like this:

One Mac (the one that is supposed to never sleep) has a Energy Saver schedule to wake up or power on every morning at 2:55 AM. It's set to not sleep, but it also has launchd jobs (cron is fine too if you want to maintain that older scheduling method) that SSH in to the client Macs.

The client Macs are set to allow wake for remote access, allow Power Nap (if supported) and set to allow SSH.

We have several AirPort and AppleTV that will proxy the ssh requests and send a wake packet to the client macs if they happen to be sleeping.

The clients then can have their cron tasks scheduled for when they wake.

If you spend too much time making this work, you can instead put a backup hook into the periodic tasks or convert them to launchd and have them run opportunistically even when the ideal scheduled time has passed.