Windows 7 sleep issues with unattended wakeup

I recently built myself a backup NAS drive using Windows-7 professional as the OS. The power profile of this system was simple.

  1. Everyday wakeup at 3:00AM and sync up between the shared-drive and backup-drive. I use the task-scheduler to set this trigger. ‘Synctoy’ is used to sync up between the drives
  2. Enable Wake-On-Lan (WOL) so that the NAS machine can be woken up remotely, say from my PC or IPhone/Ipad. I use this if i have to do any file transfers.
  3. After 30 min of inactivity go back to sleep

I tested this profile and it worked fine. And every now and then i performed maintenance by updating the OS. After that i began noticing that my NAS drive would not stay woken p for too long. Every time i woke it up using WOL or the wakeup timers in the task-scheduler, It stays awake for about 2 mins and then goes back to sleep.

I spent a lot of time trying to debug this. updating device drivers, messing with the BIOS settings etc. No change. I also observed that if the NAS was woken up from sleep using keyboard or mouse, it would stay awake for 30mins just like in the power settings (I used the balanced profile).

Searching on Google, I stumbled on this issue and its solution. It looks like Windows7 when woken up unattended (using timers, WOL) only stays awake for 120seconds by default and then sleeps if there’s no activity. Irrespective of your sleep timer setting.

If you are having the same issue, these links will hopefully help you.

In a nutshell, you either have to change the registry settings for the unattended wakeup sleep timeout and change it from 120 seconds.

I modified the entries and now my NAS box behaves as intended.


I am a computer engineer living in the beautiful city of Austin,TX. While my day job is designing computer chips, I love to dabble in woodworking, metalworking, r/c and electronics.

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Posted in Electronics

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