The Sleep Mode issue can manifest itself in a number of ways, for example, the system can wake up in some seconds after entering to sleep mode, at an arbitrary (it seems so) point of time or doesn’t fall asleep at all.

The most common reason of wakeup is the network card drivers (like LAN or Wi-Fi), USB devices or a number of background processes (usually a class of media server software, including DLNA). It should also be noted that many users face this problem right after getting updates from Windows 8 to Windows 8.1.

Power Options

Firstly, you should check power options you are using. To do it, open Power Options in the Control Panel. Find the power plan that is currently set (In our example, this is Balanced) and click Change Plan Settings button.

Why Windows 8.1 not going to Sleep Mode

Under basic power plan settings, click Change advanced power settings button.

Why Windows 8.1 not going to Sleep Mode

In the window with advanced settings of the power plan, find and expand the Sleep section. Make sure that Allow wake timers setting is disabled. If not, disable it, or Windows can wake up after certain system events.

If the Sleep button of your laptop doesn’t work correctly (single pressing the power button), make sure if both parameters in Power buttons and lid -> Sleep button action (On battery, Plugged in) are set to Sleep.

Save the changes and try to go to the Sleep Mode again. If the problem persists, let’s continue the diagnostics.

You can put your system into sleep from the command prompt. If hibernation is disabled on your PC, the command is as follows:

rundll32.exe powrprof.dll,SetSuspendState 0,1,0

If hibernation is enabled, firstly disable it:

powercfg -h off

And then run:

rundll32.exe powrprof.dll,SetSuspendState 0,1,0

Otherwise, the system will hibernate, instead of sleeping.

We also recommend to reset the settings of the currently used power plan to the standard ones. You can do it by clicking Restore default settings for this plan button in the settings of your power plan. After the changes are saved, restart your computer.

How to Detect Devices or Apps That Prevent Your PC From Going Into Sleep Mode

You can detect which apps or drivers do not give Windows go into sleep mode using powercfg. To generate a report, start command prompt as administrator and run the following command:

powercfg.exe -requests

In the results of the command will be listed processes, applications and drivers that prevent the system from falling asleep.

In our case 2 reasons that don’t allow a computer to fall asleep have been detected:

• An vlc.exe process (a mediaserver)
• High Definition Audio Device driver

You can find out the reason of the last wakeup using this command:

powercfg.exe -lastwake

This example shows that the last time the computer from sleep mode brought the network card driver.

To disable waking up the computer by a certain device, find it in the Device Manager (devmgmt.msc) and uncheck Allow this device to wake the computer in the driver properties.

How to Find Wakeup Source in the System Log

You can find the reason why your computer has woken up in the system log. To do it, open the system log (System) and apply filtering by the source of the event with the name Power-Troubleshooter.

Open the description of the last event:

The system has returned from a low power state.
Sleep Time:...
Wake Time:...
Wake Source: Device – Intel(R) USB 3.0 eXtensible Host Controller -0100 (Microsoft)

In this example some USB device has woken your computer. As a rule, it can be a mouse or a keyboard.

How to Disable Wakeup

If you found out that a USB device wakes up your system, you can disable the ability to return from the low power state for all USB devices. To do it, open the Device Manager and uncheck Allow this device to wake the computer in the Properties: USB Root Hub section.

If you are using a USB mouse, you have to uncheck this option in its properties as well.

If Nothing Helped

If neither of the methods discussed above helped to solve your problem, try the following:

• Update the drivers of all hardware to the latest versions.
• Install all the recommended updates using Windows Update.
• Leave the Homegroup and disable IPv6. (Yes, it doesn’t seem logical, but as they say in the forums it often helps).
• Update your BIOS/UEFI firmware version (pay a lot of attention if have decided to this step).