Q: How can I quickly tell which devices can wake my PC from sleep?

A: If you’re wondering why your machine is always running when you go to it each morning (is the cat jumping on your mouse?), you can quickly see the devices that can wake your machine. Just use the command below:

powercfg -devicequery wake_armed

In the example below, you can see my keyboard, mouse, and network adapter can wake my machine from sleep.

C:>powercfg -devicequery wake_armed
Microsoft USB Dual Receiver Wireless Keyboard (IntelliType Pro)
Microsoft USB Dual Receiver Wireless Mouse (IntelliPoint)
Realtek PCIe GBE Family Controller

You can change this by opening device manager (devmgmt.msc). Select the Properties of the device, and under the Power Management tab, clear the check box for the option Allow this device to wake the computer (see the screen shot below).

Also, remember to check for scheduled tasks that might be waking your machine. Just launch the Task Scheduler (taskschd.msc), and look at each scheduled task. Under Conditions, Power, make sure it’s not set to Wake the computer to run this task, unless you want it to wake the PC.

If you need to change it to not wake the machine, open the settings of the task and clear the task box labeled Wake the computer to run this task. Another option is to add your own scheduled task to put the machine back to sleep, perhaps 30 minutes after the other task. This way the actions can still be taken if your machine is turned off, but it doesn’t stay awake once it’s finished (see screen shot below).

To see more FAQs, please go to John Savill's FAQs page on Windows IT Pro.