How can I prevent my computer from waking up accidentally?

When I put my computer into sleep mode, it will wake up while I'm away from it. There's nothing near the computer that could move the mouse or accidentally press a button and I have no idea what might be causing it.

I tried checking what woke it, apparently LASTWAKE only tells me that it has been in sleep mode, not what woke it up.

I also couldn't find anything in my Power Options regarding Sleep that seems off. Poking around in the Event Viewer I notice the following:

The Power-Troubleshooter event at the top notes the following:

The system has returned from a low power state.

Sleep Time: ‎2012‎-‎10‎-‎27T11:31:53.408927000Z Wake Time: ‎2012‎-‎10‎-‎27T12:25:51.887029300Z

Wake Source: Unknown

So does anyone have an idea to find out what might be causing it and how I can prevent my computer from randomly waking up?

Solution 1:

I've had this problem before when I had network shares that were hosted on the sleeping machine, but accessed by other machines on the network. There are some settings for network cards that determine if it can wake the machine from sleep, and under what conditions:

This TechNet article explains the power management settings for network devices on Win7. There's not a Win8 version of this page yet, but I assume they are somewhat similar.

Beyond this, many other devices with similar checkboxes to allow for waking - I'd probably advise turning as many of these off as possible, and seeing if your problem persists. If it does, you might consider a binary search style approach to figure out which one is the offending sleep-disturber.

Solution 2:

If you type in your elevated command prompt powercfg /waketimers, it will display a list of scheduled tasks that will wake the computer. You might discover what could be causing this to occur.

If it is a wake timer that's causing this behavior, if you go into the Advanced power settings, under the Sleep category, you can disable Wake Timers. This might fix your issue, if this is the culprit.

For instance, I see this when executing that command:

EDIT:

Also, by the way, I did recall this occurring with my laptop once. It took a bit of troubleshooting, but I discovered that the culprit was my Microsoft Arc Touch Mouse. I discovered that the USB dongle (which received its wireless signal), caused the computer to periodically wake up, even though the mouse wasn't powered on. I fixed the issue by finding the USB device in the Device Manager and, under Properties, turning off "Allow this device to wake this computer". However, I found a more prudent solution was to just not leave it plugged into the laptop all the time. :)

Solution 3:

You should check if you have anything similar to this in your BIOS:

Setting everything to disabled at the "Power" tab should override any Windows settings.