By the end of this lesson you will be able to
- Respond to a failed or stuck update in a safe order without switching the computer off in the middle of it.
- Fix a blank screen, a wrong screen size or a missing external monitor.
- Reduce overheating with safe changes to placement, airflow and power mode.
- Check how much battery capacity is left and extend battery life with sensible habits.
- Explain why a permission error appears and fix it without weakening your security.
This lesson covers five problems that look unrelated but share one habit: do the safe, reversible thing first, and never force your way past a warning. An update that fails halfway, a screen that goes dark, a laptop that gets too hot, a battery that empties too soon and a message saying you are not allowed to do something all feel alarming. In each case there is a short, safe order of checks. Following it avoids the two things that turn a small fault into a large one: panic and random changes.
When an update fails
An update replaces parts of the system or of a program with newer versions that fix faults and security holes. An update can fail for ordinary reasons: not enough free storage, a lost internet connection halfway, another update already running, or the computer being switched off before it finished. The golden rule is: never switch off or unplug the computer while it says it is installing or configuring updates, unless it has been frozen with no sign of activity for a very long time (several hours) and you have asked for help.
- Step 1: WaitCharger plugged in
- Step 2: ReadNote the exact message
- Step 3: RestartA normal restart
- Step 4: Free spaceSeveral gigabytes
- Step 5: Try againStable internet
- Step 6: AskSearch the message
Read this figure as text
A flow of six steps from waiting and reading the message to checking space and asking for help when an update fails.
Six steps in order. Step 1, Wait: updates can take a long time, so give it at least 30 to 60 minutes and keep the charger plugged in. Step 2, Read the message: note the exact wording or error code. Step 3, Restart: restart normally once the update has stopped working, because many failures finish on restart. Step 4, Free space: make sure there are several gigabytes free. Step 5, Try again: run the updater again, with a working internet connection. Step 6, Ask for help: search the exact message on the official support site, or ask someone with your notes.
Retry an update
Ubuntu 24.04
Step 1: Open Software Updater
Press the Super key, type
Software Updaterand press Enter. It checks for updates.You should see: It lists updates, or says the software is up to date.
Step 2: Read any error
If it says 'Could not get lock', another update is already running in the background. Wait ten minutes, close the window and try again; a restart also clears it. If it says there is not enough free disk space, free storage first (see the earlier lesson in this module).
You should see: The message is clear enough to search for.
Step 3: Install and restart
Choose Install Now, keep the charger connected, and restart when asked.
You should see: The computer restarts and the updater then says everything is up to date.
Windows 11
Step 1: Open Windows Update
Go to Settings, then Windows Update. Choose Check for updates.
You should see: It lists updates or says you are up to date. A failed update shows 'Failed to install' with a code.
Step 2: Restart and retry
Restart the computer, keep it plugged in, and choose Retry on the failed update.
You should see: The update installs, or shows the same code again.
Step 3: Run the troubleshooter
Go to Settings, System, Troubleshoot, Other troubleshooters, and choose Run beside Windows Update.
You should see: It reports what it repaired. Restart, then check for updates again.
Display problems
A display problem is either nothing shown, or something shown wrongly: too large, too small, blurry, flickering or on the wrong screen. Start with the physical facts. Is the computer actually on (lights, fan noise)? Has brightness been turned right down by the brightness keys? If you use an external monitor, are the power and the cable firm at both ends, and is the monitor on the right input?
Resolution: 1920 x 1080 (recommended)
Scale: 100%
Refresh rate: 60 Hz
Orientation: Landscape
- Marker 1: Pick which screen to change
- Marker 2: Use the recommended resolution
- Marker 3: Raise the scale if text is too small
- Marker 4: A wrong refresh rate can cause flicker
- Marker 5: Revert undoes a bad change
Read this figure as text
A simulated settings window for displays with a list of screens, a resolution drop-down, a scale option and a refresh rate option.
A simulated settings window titled Displays. The sidebar lists Built-in display and an external monitor (mark 1: choose which screen to adjust). The main area shows Resolution 1920 x 1080 recommended (mark 2: use the setting marked recommended, because other values look blurry), Scale 100 percent (mark 3: increase it if text is too small), and Refresh rate 60 Hz (mark 4: a wrong or unsupported rate can cause flicker). Buttons at the bottom are Revert and Keep changes (mark 5: if the screen goes dark after a change, wait and the old setting returns).
Fix a screen that looks wrong or is missing
Ubuntu 24.04
Step 1: Open Displays
Open Settings and choose Displays. Select the screen you want to change.
You should see: You see Resolution, Scale and Refresh Rate options for that screen.
Step 2: Use the recommended resolution
Choose the resolution marked as the best match for the screen. If text is too small, raise Scale (for example to 125 or 150 percent) instead of lowering the resolution.
You should see: Text is sharp and a sensible size.
Step 3: Find a second screen
Connect the monitor cable firmly, then open Settings, Displays. In the Displays page choose how the screens relate: Join Displays, Mirror or Single Display.
You should see: The monitor shows an image in the chosen way. If it is not listed, check the cable and the monitor's input.
Step 4: Accept or revert
After a change, a box asks you to keep or revert. If the screen goes dark, do nothing for about 20 seconds and the old setting returns.
You should see: A usable screen comes back.
Windows 11
Step 1: Open Display settings
Go to Settings, System, Display. Choose the screen you want to change.
You should see: You see Scale, Display resolution and Display orientation.
Step 2: Use the recommended resolution
Set Display resolution to the value marked (Recommended). Use Scale for text size, not a lower resolution.
You should see: Text and pictures look sharp.
Step 3: Find a second screen
Press the Windows key and P together and choose Duplicate, Extend or Second screen only. If the monitor is still missing, scroll down in Display settings and choose Detect (it may be under 'Multiple displays').
You should see: The monitor shows a picture.
Step 4: Accept or revert
After a change, choose Keep changes or Revert. If you do nothing for about 15 seconds, it reverts.
You should see: A usable screen comes back.
Overheating
Processors turn electricity into heat. A fan blows that heat out through vents. If the vents are blocked or the processor is busy, the laptop gets hot, the fan becomes loud, and the processor slows itself down on purpose to protect itself. This protective slowing is called throttling. A warm laptop is normal. A laptop too hot to hold on your lap, or one that switches itself off, needs attention.
- On a bed, sofa or lap
- Vents covered
- Hot air has nowhere to go
Use a hard, flat surface or stand.
- Many programs or video calls
- A runaway program
- Processor running flat out
Close the busy program; use Balanced mode.
- Dust in vents and fan
- Years of use
- Fan always loud
Switch off to clean the outside, or ask a repair shop.
Read this figure as text
Three columns showing blocked airflow, heavy work and dust, each with a safe action to cool a laptop.
Three columns. Column 1, Blocked airflow: using the laptop on a bed, cushion or lap covers the vents; the fix is to use a hard, flat surface or a stand. Column 2, Heavy work: many programs, video calls or a runaway program keep the processor busy; the fix is to look at the monitor, close the busy program and choose a balanced or power-saving power mode. Column 3, Dust and age: dust clogs the vents and fan over years; the fix is to switch off and unplug, then clean outside vents gently, or have a repair shop clean inside. Do not open a laptop yourself.
Check the power mode
Ubuntu 24.04
Step 1: Open Power settings
Open Settings and choose Power. Look for Power Mode.
You should see: Options such as Balanced and Power Saver appear (some computers also offer Performance).
Step 2: Choose Balanced
Select Balanced for everyday work, or Power Saver to run cooler and last longer.
You should see: The fan is quieter and the laptop cooler after a few minutes.
Windows 11
Step 1: Open Power settings
Go to Settings, System, Power & battery (called Power in some versions). Find Power mode.
You should see: A drop-down offers Best power efficiency, Balanced and Best performance.
Step 2: Choose Balanced
Choose Balanced for everyday work, or Best power efficiency to run cooler and last longer.
You should see: The fan is quieter and the laptop cooler after a few minutes.
Battery problems
A laptop battery is a chemical store of energy. Every full charge and discharge, called a charge cycle, wears it a little, and heat wears it faster. After a few years, a battery holds noticeably less than when new. Capacity is how much energy it can hold now compared with when it was new. A battery that drains quickly is either being used heavily (bright screen, many programs) or has lost capacity through age.
On Ubuntu, a read-only terminal command, upower, reports the battery's current and design capacity. First upower -e lists the power devices (the battery is usually called battery_BAT0), then upower -i with that name shows the details. Neither command changes anything. On Windows, powercfg /batteryreport makes a report file that you open in a browser. It saves an HTML file in the folder shown in the message, so run it from your Documents folder if you want it tidy.
upower -i /org/freedesktop/UPower/devices/battery_BAT0powercfg /batteryreport- Marker 1: Running on battery
- Marker 2: What it can hold today
- Marker 3: What it held when new
- Marker 4: Health: today divided by new
Read this figure as text
A simulated terminal showing upower battery details with the state, energy full, energy full design and capacity lines marked.
A simulated terminal. Command: upower -i /org/freedesktop/UPower/devices/battery_BAT0. Output lines: native-path BAT0; state discharging (mark 1: the laptop is running on battery); energy 38.2 Wh; energy-full 41.0 Wh (mark 2: how much it can hold today); energy-full-design 50.0 Wh (mark 3: how much it held when new); percentage 93 percent; capacity 82 percent (mark 4: the health figure, which is energy-full divided by energy-full-design). A capacity of 82 percent means the battery holds 82 percent of what it did when new, which is good for its age.
- Lower the screen brightness. The screen is usually the biggest power user.
- Close programs and browser tabs you are not using, and switch off Bluetooth if you do not need it.
- Avoid heat. Do not leave a laptop in a hot car or under a pillow while charging.
- Do not keep it at 0 per cent. Charge before it runs flat when you can.
- Know the signs of a worn battery: it falls from 40 per cent to nothing quickly, shuts down suddenly, or the case looks swollen. A swollen battery is dangerous: stop using it, unplug it and take it to a repair shop.
Permission errors
A permission error means the system has refused an action because your account is not allowed to do it. This is the system doing its job: it stops one program, or one user, from changing things they should not. The message usually reads 'Permission denied' (Ubuntu), or 'Access is denied' or 'You need permission to perform this action' (Windows). Do not treat it as an obstacle to defeat. First ask why it is refusing.
- Belongs to the system
- Not meant for your files
Save in Documents instead.
- Owned by another account
- Private by design
Ask the owner, or copy a readable file.
- Open in another program
- Locked while open
Close the program and retry.
- File or disk marked read-only
- Camera card with its lock on
Check properties or make a copy.
Read this figure as text
Four columns showing a protected system folder, another user's file, a file that is open elsewhere and a read-only file with a safe fix for each.
Four columns. Column 1, Protected system folder: you tried to save or delete inside a folder that belongs to the operating system; the safe response is to save in your own Documents folder instead. Column 2, Someone else's file: the file belongs to another account on the computer; the safe response is to ask the owner or an administrator, or copy a readable file into your own folder. Column 3, File in use: another program has the file open; the safe response is to close that program and try again. Column 4, Read-only file or disk: the file or drive is marked as read-only; the safe response is to check the file's properties or make a copy that you can edit.
- Marker 1: Refused: /etc belongs to the system
- Marker 2: Succeeds silently in your own folder
Read this figure as text
A simulated terminal where an attempt to create a file in a protected folder fails with a permission denied message.
A simulated terminal. Command: touch /etc/example-note.txt. Output: touch: cannot touch '/etc/example-note.txt': Permission denied (mark 1: /etc holds the system's settings and ordinary accounts may not write there, which is the system protecting itself). Second command: touch ~/Documents/example-note.txt, which prints nothing (mark 2: your own Documents folder is yours, so the same action succeeds there). Lesson: the right fix is to work in your own folder, not to override the protection.
Sometimes the system asks for administrator approval (a box called User Account Control on Windows, or a password prompt on Ubuntu). This is normal when you chose to install or change something important. It is not normal if it appears when you did nothing, or after you opened an unexpected email attachment or website. In that case, choose No or Cancel and close the window. This course never asks you to type your real password into any lesson, page or simulator.
Common mistakes
✖ Instead of: Switching off the computer during 'Working on updates'.
✔ Do this: Wait with the charger plugged in. Interrupting can leave the system unable to start.
✖ Instead of: Lowering the resolution to make text bigger.
✔ Do this: Keep the recommended resolution and raise the scale.
✖ Instead of: Using the laptop on a duvet while it runs a long video call.
✔ Do this: Use a hard surface or stand so the vents stay clear.
✖ Instead of: Turning off User Account Control or changing system folder permissions to stop an error.
✔ Do this: Save to your own folders and ask for help if a trusted program needs access.
If something goes wrong
- The updater says 'Could not get lock /var/lib/dpkg/lock-frontend'.
- Another update tool is running. Wait ten minutes, then try again, or restart the computer. Do not delete anything.
- The screen went dark after I changed the resolution.
- Wait about 15 to 20 seconds without touching anything. The old setting should return. If not, force a shutdown by holding the power button and start again.
- The external monitor shows 'No signal'.
- Check the cable at both ends, choose the right input on the monitor, and use Windows key + P (Windows) or Settings, Displays (Ubuntu) to choose how to use it.
- The battery percentage jumps or the laptop shuts down at 30 per cent.
- The battery may be worn. Check its health with upower or the battery report, keep it cool, and ask a repair shop about a replacement.
Key terms
- Thermal throttling
- When a processor deliberately slows itself down to avoid getting too hot.
- Charge cycle
- One full use of a battery's capacity, added up across several partial charges, which slowly wears the battery.
- Permission
- A rule that says who may read, change or run a file or use a feature.
- Software Updater
- The Ubuntu tool that checks for and installs updates to the system and its programs.
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.
Check your battery and power mode
On Ubuntu, run upower -i /org/freedesktop/UPower/devices/battery_BAT0 (if it says the device cannot be found, run upower -e and use the battery name it lists). On Windows, run powercfg /batteryreport and open the file it saves. Write down the design capacity and the full-charge capacity, and work out the percentage. Then open your power mode setting and note which mode is chosen. Change nothing else.
Challenge: explain a permission error
Imagine Kamau tries to save a CV into a folder named Program Files and Windows says 'You need permission to perform this action'. In your own words, write four short sentences: what the message means, why Windows refuses, where Kamau should save the file instead, and one thing he must not do to get around the message.
Knowledge check
7 questions. You need 80% to pass. Mistakes here are part of learning, and you can retry as often as you like.
Summary
- Never switch off during an update. Wait, restart normally and free some space before retrying.
- Use the recommended resolution and change Scale for text size. An unwanted change can be reverted.
- Overheating is usually blocked vents or heavy work: use a hard surface and a balanced power mode.
- Battery health is full-charge capacity divided by design capacity. A swollen battery needs repair at once.
- A permission error means the system is protecting itself. Save in your own folders and never weaken security to bypass it.
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.
- Ubuntu Desktop help (Ubuntu)
- Windows support (Microsoft)