Having a computer wake up when you don’t want it to wastes electricity and drains the battery on mobile devices. My desktop had been waking up at night, so I assumed it was some network traffic on my home network. I unchecked Allow this device to wake the computer on my network adapters.
Figure 1. Network adapter Power Management tab.
That didn’t solve the problem. I included the screen capture in Figure 1 because it could be part of the solution for someone else.
To identify the root cause instead of guessing, the System log was examined. As you can see, pressing the sleep button was putting the machine to sleep.
Figure 2. Timestamp of when the computer was put to sleep.
To figure out what was waking the machine up, the System log was checked to review all events following the sleep event.
Figure 3. System log showing what woke the computer up.
This is what requested the computer to wake up:
Wake Source: Timer - Windows will execute 'NT TASK\Microsoft\Windows\TaskScheduler\Regular Maintenance' scheduled task that requested waking the computer.
A Bing search provided more information: http://support.microsoft.com/kb/2799178
To change this behavior, go to the Action Center and click on Change maintenance settings.
Figure 4. Automatic Maintenance section in the Action Center.
There are two options for modifying the Automatic Maintenance schedule. You can change the time or disable the ability for automatic maintenance to wake your device.
Figure 5. Options for controlling maintenance events waking the computer.