Do you ever put your computer to sleep or hibernate only to find it mysteriously staring at you the next morning awake?? That certainly disturbed me and I tried many things to stop my computer from being a zombie and eating brains in the middle of the night. Here’s the steps to troubleshoot and nail it on the head exactly what is happening.
Modern computer BIOSes have a host of functions for waking up the computer when it is off. Among them are the Real Time Clock (RTC) alarm that can wake up the computer on a scheduled basis (wiki), Wake On LAN (WOL) which can wakeup based on a special packet (wiki), device wake-up, and of course, the old fashion power button. Windows has a few programs that allows you to control the different features. For device wake-up, you can follow the instructions here. The post below is focused on RTC alarm which was the issue I was having.
If you are interested in killing this behavior all together and do not want to bother with everything else, simply navigate to Control Panel -> Search for “Power Options” -> On the left sidebar, “Change when the computer sleeps” -> “Change Advanced power settings”. You will see the screen below. Simply disable “Allow Wake Timers” and your computer will never wake up again by the timer when you put it to sleep.
If you are interested like me to figure out what exactly is causing the computer to wakeup, we can dive deeper into the power management system. Open a cmd prompt as administrator.
1 2 3 4 5
C:\Windows\system32>powercfg -waketimers Timer set by [PROCESS] \Device\HarddiskVolume4\Windows\System32\services.exe exp ires at 2:59:29 AM on 3/16/2013. Reason: Windows will execute 'NT TASK\Microsoft\Windows\TaskScheduler\Regular Maintenance' scheduled task that requested waking the computer.
We can see it is a scheduled task that is causing the system to wakeup at 2:59 in the morning. I’m on Windows 8, I believe the name might be different for previous versions, but you can go to Control Panel -> Search for “Scheduled” -> Scheduled Tasks. Look for the task listed above, in my case it was “Regular Maintenance”. Open that task and go to the “Conditions” tab and deselect “Wake the computer to run this task”.
After disabling that, check back with your wake timers and you should see the following:
C:\Windows\system32>powercfg -waketimers There are no active wake timers in the system.
Now you can still have wakeup timers that go off when you want them while not having the daily 3AM alarm go off.