Sleep, Hibernate and Shut Down in Windows: The Differences, and Why the Computer Won't Sleep or Wakes Up by Itself

Many people go for years without shutting down their computer — they just close the laptop lid or press "Sleep". It's convenient: work carries on from the same place. But sometimes the power-saving modes behave oddly: the computer won't sleep, switches itself on at night with its fans roaring, shows a black screen after sleep, and a laptop put away in a bag gets hot and is flat by morning. Let's look at how sleep, hibernate and shut down differ and why they misbehave.

How the modes differ

Sleep

The computer switches off the screen, drives and most components, but keeps powering the RAM, where all your open programs and documents are held. Waking from sleep takes seconds. Power use is minimal but not zero — if a desktop loses power, unsaved data is lost.

Modern Standby

Many new laptops use "Modern Standby" instead of classic sleep: the computer behaves like a smartphone with its screen off and can receive email and updates. It's convenient, but this is the mode most likely to cause draining and overheating in a bag.

Hibernate

The contents of RAM are written to the drive and the computer then switches off completely. When you turn it on, everything is restored from the same point. Hibernate uses no battery, but resuming takes longer and a file the size of your RAM occupies space on the drive.

Shut down and Fast Startup

Windows has "Fast Startup" switched on by default: when you shut down, the system partly saves its state, as with hibernation. So "shut down" isn't quite a full shutdown. A full restart is done with the "Restart" option.

Which to choose

• A short break — sleep.
• A laptop overnight or for travel — hibernate or shut down, especially if it's going in a bag.
• A desktop without a UPS — save your documents before sleeping, and it's better to shut down overnight.
• A computer running CCTV, a server or downloads — turn sleep off altogether.

Why the computer won't sleep

• A program or driver "doesn't allow" sleep: a media player, a browser playing video, a downloader, a backup program.
• Connected devices — a mouse, a gamepad, some USB devices — keep "waking" the system.
• Open shared folders or network connections in the office.
• Incorrect power plan settings.

Why the computer wakes up by itself

• Wake timers: Windows maintenance, update installation, antivirus tasks.
• A network card set to wake on LAN.
• A sensitive mouse that reacts to vibrations on the desk.
• Scheduled tasks from third-party programs.

Why there's a black screen after sleep, or the computer won't wake

Most often the graphics, chipset or power-management drivers are to blame, especially after a Windows update. The cause can also be outdated BIOS firmware, power supply problems in a desktop, overclocking or incompatible memory. If the computer regularly "freezes" when waking from sleep, it's worth diagnosing: forced shutdowns with the power button increase the risk of damaged files.

A laptop that drains and heats up in its bag

This is a risky situation: in a closed bag without ventilation, a laptop can overheat badly, shortening the life of the battery and components. The cause is Modern Standby and programs that keep running with the lid closed. The fix is to set the laptop to hibernate shortly after the lid is closed and to check which programs are interfering.

A simple habit helps too: before putting the laptop away, glance at it a few seconds after closing the lid. If the fan is still audible or the power light suggests it's fully awake, open it again and shut it down properly. Ten seconds of attention can save a battery that would otherwise wear out years early from repeated overheating.

What our technician does

1. Identifies which programs and devices are blocking sleep or waking the computer.
2. Configures the power plan, button and lid actions and wake timers.
3. Updates the graphics, chipset and power-management drivers and the BIOS.
4. Sets up hibernation on laptops so they don't drain in a bag.
5. Checks the power supply, battery and cooling system if there are hardware faults.

A real example

A lawyer in Vake put his laptop in his briefcase every evening and found it hot and flat in the morning. Sometimes it wouldn't wake from sleep at all and he had to hold down the power button. Our technician found the laptop was using Modern Standby, and a cloud client and a video-calling program kept running with the lid closed. There was also an outdated power-management driver. After the drivers and BIOS were updated and automatic hibernation was set for 15 minutes after the lid closed, the laptop was cool and charged every morning.

For a desktop, an uninterruptible power supply is a sensible companion to sleep mode: it keeps the computer safe during the short power cuts that aren't unusual in Tbilisi, so an unsaved document isn't lost just because the lights flickered.

Call a technician

If your computer won't sleep, wakes up by itself or freezes after sleep, we'll come to any district of Tbilisi around the clock. Learn more on our computer setup, driver installation and laptop repair pages.