Mac Mini Won't Wake On Schedule

At Hivelogic Headquarters, hidden deep in the Florida swamp-land, you use Retrospect as a part of your backup strategy. To avoid interfering with daily activities, the backup is set to run at 2:00 am EST.

While your G5 is usually on and running, other members of your household often have their machines set to sleep when not in use. Rather than force them to adjust practices to which they have become accustomed, you have their machines set to wake from sleep several minutes before the backup is set to start, and to go back to sleep once it’s over.

The Problem

It’s been working great on all but one machine: the Mac mini. For some reason, the mini refused to wake from sleep on a schedule. While it was no problem waking it from sleep through user-interaction such as moving the mouse or hitting a key on the keyboard, the Schedule settings in the Energy Saver System Preference panel seemed to have no effect.

The Solution

After some amount of testing and troubleshooting, researching, tweaking and deleting of plist files, you discovered the answer: reset the mini’s Power Management Unit (PMU).

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