Windows 8.1, computer does wil not go into sleep mode

Question

Awhile back I rebuilt my desktop with Windows 8 Pro. I recently update to Windows 8.1, and now it will not go to sleep. I really don't want to use all that extra power if I am asleep. Anyone have a solution?

Dave

Answer 1

1. First, check what devices are wake armed, and then disarm those you don't want to use to wake the computer.
2. Next, check the powercfg -lastwake command result quickly for a hint of what caused the last hiccup.
3. Then pop open the Event Viewer using the Power-Troubleshooting filter and look through the recent horror. Try to see if you cannot identify the problem yourself. If you see events complaining about memory errors or sleep state transitions failing, it may be worth updating to the latest UEFI/BIOS from your motherboard manufacturer, as well as all the latest stable signed drivers from each manufacturer. If you decide to update the UEFI/BIOS, do so very, very carefully and only after reading all the documentation.
4. Also, check the wake timers, and (optional) if you're like me, go ahead and joyfully disable all the non-critical tasks, but only if you're prepared to take risks.
5. Run Windows Update until it's done and happy. Then run it again just to be sure. Then reboot the system once more for good measure.
6. If none of this works, you can try eliminating all non-critical devices connected to the system's inside and outside (i.e. PCI, USB...) -- unplug it all! -- just to see if you can keep your precious offsping asleep for a few hours without the wake issues.
7. If that fails and you see new RAM or sleep state transition errors in the Event Viewer, then consider checking the RAM's compatibility with the CPU and chipset, as well as whether the RAM and CPU are clocked properly.
8. Also, check your chipset/motherboard manual for information about any EPU-like (ASUS makes onboard switchable Energy Processing Units) or power management or auto-overclocking done on your board. You might be surprised to see the innovative.... attempts at managing power... and how the fail miserably when we install the wrong RAM because we didn't read the manual....

I assumed that your system is prevented from sleeping or continuing sleeping. If it seems it's not going to sleep at all, you might want to start by checking the Power Options panel in the Control Panel. There's another question on SuperUser about this that might be of interest.