Guide Windows 11 Problems & Fixes – The Complete Troubleshooting Guide for 2026

Unison

Unison

Well-known member
VIP

Windows 11 Problems & Fixes – The Complete Troubleshooting Guide for 2026​

Windows 11 is generally reliable, but sooner or later most users run into problems such as a slow PC, failed updates, high CPU or memory usage, Wi-Fi dropping out, no sound or applications refusing to work correctly.

Rather than immediately reinstalling Windows, there are quite a few things worth checking first.

This guide covers some of the most useful Windows 11 troubleshooting steps and commands in one place.

1. Windows 11 Running Slow​

Start by opening Task Manager:

Ctrl + Shift + Esc

Check the Processes tab and click the CPU, Memory or Disk column to see what is consuming resources.

Also check:

Settings → Apps → Startup

Disable applications you don't need starting automatically with Windows.

Don't disable something simply because you don't recognise its name. Look it up first.

2. Repair Corrupt Windows System Files​

Open Terminal or Command Prompt as Administrator and run:

sfc /scannow

System File Checker scans protected Windows files and attempts to repair damaged or missing files.

If SFC reports problems it cannot repair, try:

DISM /Online /Cleanup-Image /RestoreHealth
When DISM has finished, restart the PC and run:

sfc /scannow
again.

3. Windows Update Problems​

If Windows Update appears stuck, first try:

Settings → System → Troubleshoot → Other troubleshooters

You can also check Windows itself for corruption using the SFC and DISM commands above.

Make sure there is sufficient free disk space before installing a major Windows update.

4. Wi-Fi or Ethernet Not Working​

First check the network configuration.

Open Command Prompt and enter:

ipconfig /all
To test whether the PC can reach the internet:

ping 1.1.1.1
Then try:

ping google.com
If the first works but the second doesn't, there may be a DNS problem.

You can clear the Windows DNS cache with:

ipconfig /flushdns
Another useful command is:

nslookup google.com
This can help determine whether DNS resolution is working.

5. Reset the Windows Network Stack​

For stubborn networking problems, open Terminal as Administrator and try:

netsh winsock reset
followed by:

netsh int ip reset
Restart Windows afterwards.

Remember that resetting networking can remove or reset customised network settings, so don't use it unnecessarily on a specially configured PC.

6. High CPU Usage​

Open Task Manager and sort the processes by CPU.

Common causes include:

  • Windows Update
  • Antivirus scans
  • Web browsers with many tabs
  • Background applications
  • Faulty drivers
  • Software stuck in a loop
Don't immediately terminate an unfamiliar Windows process. Search for the process name first and establish what it belongs to.

7. High Memory Usage​

In Task Manager, click Memory to see which applications are using the most RAM.

Browsers can consume several gigabytes when many tabs are open.

Also check:

Task Manager → Startup apps

Removing unnecessary startup applications can considerably reduce memory usage after booting.

8. Disk Usage Stuck at 100%​

Open Task Manager and sort by Disk.

If one application is constantly accessing the drive, investigate that application first.

You can also check the Windows drive for filesystem errors:

chkdsk C: /scan
If you are using an older mechanical hard drive, sustained high disk activity can make Windows feel extremely slow even when CPU and memory usage are relatively low.

9. Check How Much Free Disk Space You Have​

Open:

Settings → System → Storage

Windows needs free space for updates, temporary files and normal operation.

Storage Sense can also remove unnecessary temporary files automatically.

Be careful when manually deleting folders. Never delete Windows system directories simply to recover space.

10. No Sound in Windows 11​

Start with:

Settings → System → Sound

Check that Windows has selected the correct output device.

This is particularly important if you have several devices such as:

  • HDMI audio
  • USB headset
  • Bluetooth headphones
  • Monitor speakers
  • Motherboard audio
Windows can occasionally switch the default output after an update or when a new device is connected.

11. Check Windows Drivers​

Open Device Manager and look for devices showing warning symbols.

For graphics drivers, it's normally best to obtain the appropriate driver from NVIDIA, AMD, Intel or the PC/device manufacturer.

Avoid random "driver updater" utilities downloaded from unknown websites.

12. Check Windows Security​

Open:

Windows Security → Virus & threat protection

Make sure protection is enabled and definitions are current.

You can perform a Quick Scan or Full Scan if you suspect unwanted software.

For most home users, Microsoft Defender provides the security protection already built into Windows 11.

13. Find Your Windows 11 Version​

Press:

Windows key + R

and enter:

winver
This displays the Windows release and OS build.

This information is extremely useful when asking for technical support.

14. Find Your PC Specifications​

Press:

Windows key + R

and enter:

msinfo32
For DirectX, graphics and audio information:

dxdiag
For basic command-line system information you can also use:

systeminfo

15. Check Windows Reliability History​

One of the most useful Windows troubleshooting tools is often overlooked.

Search the Start menu for:

View reliability history

Reliability Monitor displays application crashes, Windows failures and other problems on a timeline.

If a PC suddenly started behaving badly, this can help identify exactly when the trouble began.

16. An Application Keeps Crashing​

Before reinstalling Windows, try:

  1. Restarting the PC.
  2. Updating the application.
  3. Checking Reliability Monitor.
  4. Checking for Windows updates.
  5. Updating the relevant hardware driver.
  6. Repairing or reinstalling the application.
  7. Running SFC if Windows corruption is suspected.
Changing one thing at a time makes troubleshooting much easier.

17. Windows 11 Takes Too Long to Boot​

Open:

Task Manager → Startup apps

Look at applications with a high startup impact.

Disable programs you don't need immediately after logging in.

Also check that the Windows drive isn't nearly full.

If Windows is installed on an old mechanical hard drive, upgrading to an SSD can make a dramatic difference to boot and application loading times.

18. Useful Windows 11 Troubleshooting Commands​

Here is a quick reference worth bookmarking:

sfc /scannow
DISM /Online /Cleanup-Image /RestoreHealth
ipconfig /all
ipconfig /flushdns
ping 1.1.1.1
ping google.com
nslookup google.com
netsh winsock reset
netsh int ip reset
chkdsk C: /scan
systeminfo
Some of these require an Administrator Terminal.

19. Before Reinstalling Windows​

A complete reinstall should usually be one of the later options rather than the first.

Before doing it, consider:

  • Restarting the PC
  • Checking Task Manager
  • Installing Windows updates
  • Checking drivers
  • Running SFC
  • Running DISM
  • Checking Reliability Monitor
  • Testing the SSD/HDD
  • Checking temperatures
  • Testing memory
  • Removing recently installed problematic software
And most importantly:

Back up anything important before making major repairs or reinstalling Windows.

Getting Help​

If you're still having a Windows 11 problem, post the details of the problem along with:

  • Windows 11 version/build
  • PC specifications
  • Exact error message
  • When the problem started
  • Anything changed immediately beforehand
  • Troubleshooting already attempted
Screenshots are also extremely useful.

Someone may have experienced exactly the same problem and be able to help.

What Windows 11 problem brought you here?

Post it below and we'll see if we can get it sorted.
 
You must log in or register to reply here.
Back
Top