It happens at times that the windows machine wakes up randomly from sleep mode. Here are some steps you may be able to follow to identify the cause and address the issue :
Find out the cause of the wake :
You may see the Device that woke the computer up as the output of the above command. If you do not see anything, that means there could have been a generic wake up timer set by some application, then you can issue the following command mode run as administrator :
Here you will see an output with the Service Info, for example, mine was caused by teamviewer :
C:\Windows\system32>powercfg -waketimers Timer set by [SERVICE] \Device\HarddiskVolume6\Program Files (x86)\TeamViewer\Te amViewer_Service.exe (TeamViewer) expires at 1:12:18 AM on 8/5/2015. Reason: generic
Now you can either just disable wake timers completely . Go to power options and then select “Sleep” option and then disable “wake timers”.
or you can disable the timer just for the application, in application settings if available.
The other way to find out the application or service causing the wake is to look at the event viewer logs.
Launch Event viewer by issuing the command :
Then go to Windows Logs and then right click on the System > Filter Current Log. In the Event Sources drop down select “Power-Troubleshooter” , click Ok and you will see a list of Logs on when and why your system was woke up.
To find out the list of devices that are able to wake up the computer, issue the following command :
powercfg -devicequery wake_armed
And to disable a device from above list :
powercfg -devicedisablewake "name of device from above command"
To enable a device from above list :
powercfg -deviceenablewake "name of device from above command"