What is the difference between sleep and hibernate?
These two modes are similar in some ways, but very different in others. In sleep mode the computer continues to use power, but all the components are put into a very low power state.
The disk stops spinning, the CPU slows to a crawl, and anything that can be shut down is shut down.
Waking the computer from sleep, such as by pressing a key, is fast because it is already powered and running. It wakes those components that were sleeping, like the disk drive, and it continues from the exact point when it entered sleep mode.
To put the computer into sleep mode just close the laptop's lid or click Start > Power > Sleep. The computer uses a tiny amount of mains or battery power when it is sleeping and it can be woken at any time by pressing a key.
Hibernation is similar to sleep in that you can put the computer into hibernation mode and then wake it and carry on exactly where you were before. Everything is saved, including applications and windows, and they are restored on waking.
With hibernation the computer’s state is saved to disk and the power is turned off completely. This means that it uses no mains or battery power while in hibernation. The computer is woken by pressing the power button (because it is powered off). It then loads the previous state from disk.
Hibernation is selected on the Start > Power menu.
No hibernate option?
If you do not see Hibernate on the Power menu, find Command Prompt on the Start menu. Right click it and select Run as administrator. Then type:
powercfg.exe /hibernate on
(Change the on to off to turn off hibernation.)
If you cannot wake computer from sleep
Check the power
Make sure that the computer is plugged into the mains power and that the power is turned on. If a laptop is sleeping on the battery and the battery runs out, you will not be able to wake it until the power is plugged in.
Check the keyboard
If the desktop PC or laptop enters sleep mode, but you then cannot wake it, check the keyboard settings. They may be wrong.
In Windows 10 right click the Start button and then click Device Manager. In Windows 7 click Start, enter ‘device manager’ and then click it in the search results.
Expand the Keyboards section, right click the keyboard entry and select Properties on the menu.
Select the Power Management tab and then tick Allow this device to wake the computer.
Try the troubleshooter
There are many Windows Troubleshooters that can automatically fix problems and they are worth trying. They do not always work, but sometimes they do.
Open the Control Panel and in small icons view, click Troubleshooting. or type 'Troubleshooting' into the search box.
Click View all and then click Power. Run the troubleshooter and afterwards, try putting the computer into sleep mode again and see if you can wakes it.
It might be worth running the System Maintenance troubleshooter too.
Update the drivers
Sleep and hibernation problems might be caused by old, buggy or outdated drivers. New ones might fix the problem. There are several ways to update them and one is by using Device Manager.
Open Device Manager as described above. Expand a section, such as Display adapters. Right click the display adapter and then select Update Driver Software.
Repeat this with the items under Bluetooth, Mice and pointing devices, Audio inputs and outputs, Network adapters, and Sound, video and game controllers.
Another way to update drivers is to go to the computer manufacturer’s website. Look for the drivers for the computer you have.
For example, go to https://support.hp.com/redirect/hub/s-002 for HP drivers and enter the computer model name to find them.
While on the subject of HP computers, HP says that MEI driver version 9 or 10 from the Driver-Chipset section fixes some sleep problems. You might get a warning about replacing a newer driver with an older one, but continue anyway.
If you have a Dell computer, go to www.dell.com/drivers. Other manufacturer’s have similar download options.
A third party driver update utility can find drivers that are hard to get or if you don’t know the exact model of your computer.
Get IObit Driver Booster Free. Avoid installing any optional extras during installation because you don’t need them. Run the Driver Booster, but do not update all the drivers in one go.
Update only one driver at a time and test the computer. If it is OK, update another driver.
Check for power requests
Earlier we saw a command prompt tool to turn hibernation on. The same command can also be used to check if anything is preventing the computer from entering sleep mode.
Find Command Prompt on the Start menu, right click it and select Run as administrator. Enter:
Check the output from this command for clues. Anything that is listed could potentially prevent sleep mode.