Running Windows 8 lately I have noticed a new trend that was causing me grief. I would sleep or hibernate my desktop every night, and yet when I woke up in the morning, there it would be, screens dark, but fans spinning and fully awake. First I was just sleeping the machine, and I figured the reason it was awake in the morning was due to a cat walking across the keyboard at night. I started to hibernate it, knowing that a cat can not push a power button.
So it finally bothered me enough to take a look a and see if I could figure out what was waking it up. I opened up an elevated command prompt and typed “powercfg /waketimers”
The reply was:
Timer set by [PROCESS] \Device\HarddiskVolume3\Windows\System32\services.exe expires at 2:59:41 AM on 5/23/2012. Reason: Windows will execute 'NT TSK\Microsoft\Windows\TaskScheduler\RegularMaintenance' scheduled task that requested waking the computer.
Pretty obvious there, Regular Maintenance wakes up my computer every day at 03:00 AM. Nice. Wait, what is regular maintenance? I open up my Windows 8 Search box and type in “maintenance” and the top result is “Automatic Maintenance” It runs by default every day at 03:00 AM and by default the check box is set to “Allow Scheduled Maintenance to wake my computer if it is plugged in at the scheduled time”
I unchecked the box, and now my computer will sleep well tonight.