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Sleep, restart, shut down and frozen computers

Know when to use sleep, restart or shut down, protect your work before you power off, and deal calmly with a frozen program or computer, using the power button only as a last resort.

25 minbeginnerUbuntu/LinuxWindowsPractical task needs a laptop or desktop

Marking a lesson as read does not prove you can do it. Skills count as demonstrated when you pass the quiz (not yet) and complete the practical tasks (not yet).

By the end of this lesson you will be able to

  • Explain the difference between sleep, hibernate, restart and shut down.
  • Choose the right power option for a situation.
  • Save work before powering down and know what is lost if you do not.
  • Close a frozen program using the force-quit tools on Ubuntu and Windows.
  • Follow a calm step-by-step order when the whole computer is frozen.

Every computer user meets a frozen screen sooner or later, and the panic that comes with it. Knowing the power options and the calm order of steps turns a frightening moment into a routine one. This lesson also explains why you should save as you go, because the computer cannot rescue what it never kept.

The four ways of stopping

When you finish, you have four choices. They differ in how much of your work is kept, how much power is used and how long the next start takes. The key fact from the start-up lesson is that RAM (memory) forgets everything when power is lost, while storage remembers.

{{sleep-mode|Sleep}} keeps your open programs in RAM and uses a tiny trickle of power. Waking takes seconds. Ubuntu calls this Suspend. {{hibernation|Hibernate}} copies the contents of RAM into storage and then switches off completely, so it uses no power; waking takes longer but your programs return. Restart closes everything and starts the computer again from the beginning. Shut down closes everything and switches the power off.

Diagram

What each power option does with your open programs and your power.

SleepCalled Suspend on Ubuntu
  • Programs stay in RAM
  • Tiny trickle of power
  • Wakes in seconds

Short breaks.

Hibernate
  • RAM saved to storage
  • No power used
  • Wakes more slowly

Long gaps, work kept. Not always offered.

Restart
  • Everything closes
  • Starts again at once
  • Finishes updates

Fixes small glitches.

Shut down
  • Everything closes
  • Power off
  • Next start is a full boot

Hours or days away.

What each power option does with your open programs and your power.
Read this figure as text

Four columns comparing sleep, hibernate, restart and shut down.

Sleep: programs stay in RAM, a little power is used, wakes in seconds, the battery slowly drains. Hibernate: RAM is saved to storage, no power is used, wakes in under a minute, programs come back. This option is not always switched on in the menu. Restart: everything is closed and the computer boots again; use it to finish updates and fix small glitches. Shut down: everything is closed and the power is off; the next start boots from scratch.

Which one should I use?

  • Back in a few minutes or a few hours: sleep, or just close the lid. Waking is quick.
  • Not using it until tomorrow or longer, or travelling: shut down. A sleeping laptop in a bag can warm up and drain the battery.
  • Updates are waiting, or the computer feels slow or odd: restart. This clears out many small problems.
  • Someone else will use the laptop: log out, or shut down.
Diagram

A short guide to picking a power option.

  • Will you be away for many hours, or carrying the laptop in a bag?
    • YesDo thisEverything closes and the power goes off. Safe for travel and long gaps.
    • NoIs it slow, behaving oddly, or waiting for updates?
      • YesDo thisCloses everything and starts afresh. Finishes updates and clears glitches.
      • NoDo thisQuick break. Your work stays open and wakes in seconds.
A short guide to picking a power option.
Read this figure as text

A yes or no decision tree that ends in sleep, restart or shut down.

Start: are you finished with the laptop for several hours, or travelling with it? If yes, shut down. If no: is it behaving oddly, or does it say updates are waiting? If yes, restart. If no, you are just taking a break, so use sleep or close the lid.

Where to find the options

  1. Step 1: Open the system menu

    Click the system menu in the top-right corner of the screen, where the Wi-Fi, sound and battery icons are.

    You should see: A panel of quick settings opens.

  2. Step 2: Open the power list

    Click the power button symbol at the bottom of the panel, which opens a short list.

    You should see: You see choices such as Suspend, Restart, Power Off and Log Out. In some releases the menu is a single Power Off / Log Out item that opens a further list.

  3. Step 3: Choose an option

    Choose Suspend for sleep, Restart to restart, or Power Off to shut down. A confirmation box may appear with a countdown.

    You should see: Click the button in the box or wait for the countdown.

Save first, always

Remember the four jobs: processing happens in memory, and memory forgets. A document you have typed but not saved lives only in RAM. If the power fails, the laptop crashes or you force a program to quit, that work may be gone. Save with Ctrl + S every few minutes. Many programs also keep an automatic recovery copy, but you should not rely on it.

When something freezes

A frozen program stops answering clicks and key presses. The window may turn pale, the pointer may become a spinning circle, or the title bar may say “Not responding”. Often the program is busy with a big task and will recover. The key skill is to go from the gentlest action to the most forceful, and to stop as soon as it works.

Diagram

The calm order of steps for a frozen program or computer.

  1. Step 1: WaitOne or two minutes
  2. Step 2: Close normallyClose button or Alt + F4
  3. Step 3: Force quitTask Manager or System Monitor
  4. Step 4: RestartFrom a menu if reachable
  5. Step 5: Hold powerLast resort, 5 to 10 seconds
The calm order of steps for a frozen program or computer.
Read this figure as text

A flow of five steps from waiting to using the power button as a last resort.

Five steps, gentlest first. Step 1: wait for one to two minutes, because the program may just be busy. Step 2: try to close the program normally with its close button. Step 3: use force quit, which is End task in Windows Task Manager, or Force Quit in the Ubuntu prompt or System Monitor. Step 4: if the whole computer does not react at all, wait a little longer, then restart it from the keyboard menu if you can reach one. Step 5: last resort, hold the power button for several seconds to cut the power. Unsaved work is lost at steps 3 to 5.

To force quit is to make the operating system stop a program straight away. It is the computer equivalent of pulling a chair from under a guest. The program has no time to save anything. That is why it comes after waiting.

Force quitting a frozen program

  1. Step 1: Wait first

    Wait a minute. Ubuntu often shows a box saying the program is not responding, with the buttons Force Quit and Wait.

    You should see: If you see the box, choose Wait first. If nothing changes after another minute, choose Force Quit.

  2. Step 2: Open System Monitor

    If no box appears, open Activities in the top-left, type System Monitor and open it.

    You should see: A window lists running programs and shows their processes.

  3. Step 3: End the program

    Click the Processes tab, find the program by name, right-click it and choose End. If it still stays, right-click again and choose Kill.

    You should see: The program disappears from the list and its window closes.

Simulated interface: not a real screenshot

A simulated process list with one program not responding.

Task Manager (simulation)
BrowserRunning
Document editorNot responding
Music playerRunning
End task
  1. Marker 1: The app that is not responding
  2. Marker 2: End task closes it by force
A simulated process list with one program not responding.
Read this figure as text

A simulated task manager window listing apps, with one marked as not responding and a button to end it.

A simulated window titled Task Manager with a list of running apps. The first row, Browser, is running normally. The second row, Document editor, is marked Not responding and is selected, shown as marker 1. A button at the bottom, End task, is marker 2. The third row, Music player, is running normally. The wording is generic and the real tool differs by system.

When the whole computer is frozen

If even the pointer will not move and no key does anything, wait a full two minutes, because a computer that is working hard can look dead. Try pressing Caps Lock: if its light does not respond, the system really is stuck. Then, only after waiting, hold the power button for five to ten seconds until it switches off. Wait ten seconds, then press it once to start again. The computer may check its drive and take longer to start. Any unsaved work is lost, and this is the one situation where holding the button is acceptable.

Diagram

Working out whether one program or the whole computer is frozen.

  • Does the pointer move when you move the mouse or touchpad?
    • YesDo other programs respond?
      • YesDo thisWait a minute, then End task (Windows) or End/Force Quit (Ubuntu) for that program only.
      • NoDo thisWait. Try to restart from the power menu. If you cannot reach it, treat it as a frozen computer.
    • NoDo thisWait two minutes. If nothing changes, hold the power button for five to ten seconds, wait, then start again.
Working out whether one program or the whole computer is frozen.
Read this figure as text

A decision tree that separates a single frozen program from a frozen computer.

Start: does the pointer move when you move the mouse or touchpad? If no, wait two minutes; if still no, the whole computer is frozen, so use the power button as a last resort after waiting. If yes: do other programs respond? If yes, only one program is frozen, so wait and then end that program with Task Manager or System Monitor. If no, several programs are stuck, so wait, then try to restart from the menu.

Common mistakes

  • ✖ Instead of: Using the power button as the normal way to switch off.

    ✔ Do this: Use Shut down from the menu so programs can close and save. Keep the button for a computer that is completely frozen.

  • ✖ Instead of: Closing the lid on a laptop in a bag and assuming it is off.

    ✔ Do this: Closing the lid usually triggers sleep. For travel, shut down fully.

  • ✖ Instead of: Force quitting at the first sign of slowness.

    ✔ Do this: Wait one or two minutes first. Many programs are only busy, and force quitting loses unsaved work.

  • ✖ Instead of: Ending processes in Task Manager that you do not recognise.

    ✔ Do this: Only close apps that you opened yourself. Some processes keep the system running.

If something goes wrong

The laptop will not wake from sleep.
Press the power button once, not a long press. Check that it is plugged in or charged. If nothing happens, hold the power button for ten seconds to switch off, then start it again.
I cannot find Hibernate in the power menu.
That is normal on many laptops, since it is not enabled by default. Use sleep or shut down. Do not change advanced settings until you are comfortable with the basics.
Task Manager or System Monitor will not open because the computer is too slow.
Wait a couple of minutes and try again. If it still will not open, treat it as a frozen computer and follow the last-resort steps.
After a forced power-off the computer shows a recovery or repair message.
Let it finish. It is checking for damage from the sudden power loss. Do not interrupt. If it repeats every time, ask a technician.

Key terms

Sleep mode
A low-power state that pauses the computer so it wakes quickly with your work still open.
Hibernation
A power state that saves your open work to storage and switches the computer fully off.
Frozen program
A program that has stopped reacting to clicks and keys, although the rest of the computer may still work.
Force quit
Making the operating system stop a program immediately, without letting it save or tidy up.

Practise it for real

Reading is not the same as being able to do it. Complete these on your own computer, then tick only what you have actually done. These ticks are your own honest record: nothing checks them for you.

Guided exerciseNeeds a laptop or desktop

Find every power option on your computer

Save any open work first. Open the power menu on your computer (Ubuntu system menu or the Windows Start menu). Write down which options you can see: sleep, restart, shut down, hibernate, log out. Use Sleep, wake the laptop by pressing a key or the power button, then log in if asked. Finally use Restart and note how long it takes to return to the desktop.

You have succeeded when:
Independent challengeNeeds a laptop or desktop

Challenge: find your task tool before you need it

Without waiting for a freeze, open Task Manager (Ctrl + Shift + Esc on Windows) or System Monitor (search for it in Activities on Ubuntu). Open a harmless program such as a calculator, find it in the list, and close it from the tool using End task or End. Do not touch any program you did not open yourself, or any process whose name you do not recognise.

You have succeeded when:

Knowledge check

7 questions. You need 80% to pass. Mistakes here are part of learning, and you can retry as often as you like.

  1. Question 1.Match each power option to what it does.
  2. Question 2.Joseph is putting his laptop into a bag for a long bus journey. Which option is best?
  3. Question 3.If you type a document and do not save it, it is safely kept in memory even after a power cut.
  4. Question 4.Put these steps for a frozen program in order, gentlest first.
    1. Force quit with Task Manager or System Monitor
    2. Close it normally with its close button
    3. Hold the power button as a last resort
    4. Wait a minute or two
  5. Question 5.Wanjiru's word processor shows “Not responding”, but her other programs work and the pointer moves. She has a long unsaved report open in it.What is the best next move?
  6. Question 6.Windows seems slow and strange after days of use. Which choice is more likely to clear the problem?
  7. Question 7.It is safe to hold the power button when the screen says “Installing updates, do not turn off your computer”.

Summary

  • Sleep keeps programs in RAM; hibernate saves to storage; restart starts afresh; shut down switches off.
  • Sleep for short breaks, shut down for long gaps and travel, restart to clear glitches and finish updates.
  • Save with Ctrl + S as you go, because RAM forgets when power is lost.
  • For a freeze, go gentle to forceful: wait, close normally, End task or Force Quit, restart, power button last.
  • Never cut power during an update.

Checklist: can you do these?

Marking a lesson as read does not prove you can do it. Skills count as demonstrated when you pass the quiz (not yet) and complete the practical tasks (not yet).

Related lessons

References and further reading

Official sources for details that can change between versions.

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