Most Windows 11 problems, from a slow PC to a Start menu that will not open, are fixed with the same few steps: restart, install updates, update or roll back the relevant driver, and repair system files with sfc /scannow. This guide lists the 15 problems we see most often, with the quickest fix for each and a link to a detailed guide where one exists.
Work through the fixes in order. They start with the least disruptive and only move on to resets or reinstalls when nothing else works.
| # | Problem | Try this first |
|---|---|---|
| 1 | Slow performance | Restart; disable startup apps in Task Manager |
| 2 | High CPU usage | Task Manager > Processes, sort by CPU |
| 3 | Updates fail or get stuck | Free up space; run the Windows Update troubleshooter |
| 4 | "Activate Windows" watermark | Settings > System > Activation |
| 5 | Wi-Fi keeps dropping | Update the network driver; Network reset |
| 6 | Bluetooth not working | Toggle Bluetooth; remove and re-pair the device |
| 7 | Printer not working | Restart the Print Spooler service; reinstall the printer |
| 8 | Start menu will not open | Restart Windows Explorer |
| 9 | Search not working | Restart Windows Explorer; check indexing settings |
| 10 | Taskbar missing or frozen | Check auto-hide; restart Windows Explorer |
| 11 | No sound | Check the output device in Settings > System > Sound |
| 12 | Black screen | Press Windows key + Ctrl + Shift + B |
| 13 | Battery drains fast | Check Battery usage; turn on Energy saver |
| 14 | File Explorer slow or freezing | Clear File Explorer history; check network drives |
| 15 | Random crashes or restarts | Check Event Viewer and Reliability Monitor |
What should I try first for any Windows 11 problem?
Start with a full restart, then install all updates from Settings > Windows Update, including optional driver updates. If the problem continues, repair system files: open Terminal (Admin) and run DISM /Online /Cleanup-Image /RestoreHealth, then sfc /scannow. These three steps resolve a large share of everyday faults.
Use Restart rather than Shut down. With Fast Startup turned on, a shutdown saves part of the system state and restores it next time, so a restart is the only way to fully reload Windows.
It also helps to know your exact version. Our guide to checking your Windows 11 version and updating to 26H2 shows how, and explains why staying on a supported version matters. Windows 11 version 24H2 Home and Pro stop receiving updates on 13 October 2026.
What we commonly see: a problem that "started on its own" turns out to have begun the day a driver or app was installed. Reliability Monitor, covered in problem 15, makes that link obvious.
Why is Windows 11 running so slowly?
A slow Windows 11 PC is most often caused by too many apps launching at start-up, background programs using memory, a nearly full system drive or a PC that has not been restarted for days. Open Task Manager with Ctrl + Shift + Esc, review Startup apps, and disable anything you do not need at sign-in.
- In Task Manager, select Startup apps, right-click unneeded entries and select Disable.
- Check free space in Settings > System > Storage, and turn on Storage Sense to clear temporary files automatically.
- Uninstall programs you no longer use from Settings > Apps > Installed apps.
- Run a full scan in Windows Security > Virus & threat protection > Scan options.
Cause and effect: when the system drive gets very full, Windows has less room for its page file and update files. That shows up as general sluggishness, and later as failed updates too.
Why is my CPU usage so high in Windows 11?
High CPU usage is usually one process working hard, such as Windows Update, antivirus scanning, search indexing or a misbehaving app. Open Task Manager, select Processes and sort by the CPU column to find it. Short spikes after start-up or updates are normal; constant high usage from one app is not.
If the culprit is an app, update or reinstall it. If it is a system process such as Antimalware Service Executable or Windows Modules Installer Worker, let it finish its scan or update before judging.
Constant high usage from System or System interrupts often points to a driver. Our guide to finding and updating Windows 11 drivers covers updating or rolling back the culprit.
Why do Windows 11 updates keep failing?
Windows 11 updates most often fail because of low disk space, a corrupted update cache, damaged system files or an interrupted download. Free up at least several gigabytes of space, then run the Windows Update troubleshooter from Settings > System > Troubleshoot > Other troubleshooters. Restart and select Check for updates again.
If an update still fails, run the DISM and SFC repair commands above, then try again. Note the error code shown on the Windows Update page, as it points to the specific cause.
As a last resort before resetting, go to Settings > System > Recovery and select Reinstall now under Fix problems using Windows Update. Microsoft's guide to reinstalling the current version of Windows confirms this keeps your apps, files and settings.
Why does Windows 11 say it is not activated?
An "Activate Windows" watermark means Windows cannot confirm a valid licence for your edition. Common causes are a major hardware change such as a new motherboard, a key for a different edition, a reinstall without the original key, or an invalid key. Check the status in Settings > System > Activation, where Windows shows the error and offers the Troubleshoot option.
The error code tells you what to do next. Our guides explain the two most common: error 0xC004F050, the invalid product key error, and error 0x803FA067 after a hardware change.
An unactivated PC still runs, but personalisation settings are locked and the watermark stays. If you need a new licence, a genuine Windows 11 Pro key or Windows 11 Home key activates through the same Activation page. Avoid KMS scripts and "activator" tools, which can carry malware and do not provide a valid licence.
Why does my Wi-Fi keep disconnecting in Windows 11?
Wi-Fi drops in Windows 11 are usually caused by an outdated network driver, power-saving settings on the adapter, or a router problem. Update the Wi-Fi driver from your PC maker or Windows Update's optional updates first. If that fails, use Settings > Network & internet > Advanced network settings > Network reset.
- Restart the router and the PC to rule out a temporary fault.
- Check whether other devices also drop. If they do, the problem is the router or broadband connection.
- Update the Wi-Fi driver, then run the Network and Internet troubleshooter under Other troubleshooters.
- Use Network reset and select Reset now. This removes and reinstalls network adapters and resets their settings, so you will need to reconnect to Wi-Fi and reinstall any VPN software afterwards.
Advanced nuance: if Wi-Fi only drops after the PC wakes from sleep, open the adapter in Device Manager and look at the Power Management tab. Unticking Allow the computer to turn off this device to save power, where it appears, often stops it.
Why is Bluetooth not working in Windows 11?
Bluetooth usually fails because it is switched off, the device is paired in a broken state, or the Bluetooth driver needs updating. Go to Settings > Bluetooth & devices, turn Bluetooth off and on, then remove the problem device and pair it again. If the Bluetooth toggle is missing entirely, the adapter driver is missing or disabled.
Check Device Manager for a Bluetooth category. If it is missing or shows a warning triangle, update or reinstall the driver from your PC maker's support page.
Bluetooth headphones that connect but give poor sound quality may be using the hands-free profile. Select the stereo output, not the hands-free one, in the sound settings.
Why won't my printer work on Windows 11?
Printer problems are most often caused by a stuck print queue, a stopped Print Spooler service or an outdated printer driver. Cancel all jobs in the queue, then restart the Print Spooler service. If that fails, remove the printer from Settings > Bluetooth & devices > Printers & scanners and add it again.
- Press Windows key + R, type
services.mscand press Enter. - Find Print Spooler, right-click it and select Restart.
- In Printers & scanners, select the printer and choose Remove, then Add device.
- Install the latest driver or software from the printer maker's website if Windows' built-in driver lacks features.
For network printers, check that the printer and PC are on the same network, and that the printer's IP address has not changed.
Why are the Start menu, search or taskbar not working?
When the Start menu, search box or taskbar stops responding, restarting Windows Explorer usually fixes it. Press Ctrl + Shift + Esc, find Windows Explorer under Processes, right-click it and select Restart. The taskbar and desktop briefly disappear, then reload. If the problem returns, repair system files with DISM and SFC.
If the taskbar keeps vanishing, check Settings > Personalization > Taskbar > Taskbar behaviors and make sure Automatically hide the taskbar is off. On multi-monitor setups, the same section controls which displays show it.
If search returns no results for files you know exist, open Settings > Privacy & security > Searching Windows and check which locations are indexed. Rebuilding the index under Advanced indexing options takes a while, but fixes stale results.
What we commonly see: Start and search problems that appear straight after a feature update and clear themselves after the next cumulative update. Installing all pending updates is worth trying before deeper repairs.
Why is there no sound on my Windows 11 PC?
No sound is most often caused by the wrong output device being selected, especially after plugging in headphones, a monitor or a dock. Open Settings > System > Sound and choose the correct device under Output, then check its volume. If the right device is missing, update or reinstall the audio driver.
Check the obvious things too: muted speakers, a disconnected cable or a monitor without built-in speakers selected as output. The Audio troubleshooter under Other troubleshooters checks these automatically.
If sound stopped after an update, open Device Manager, expand Sound, video and game controllers and use Roll Back Driver on the audio device.
Why is my Windows 11 screen black?
A black screen can mean a graphics driver has stopped responding, the PC is sending video to the wrong display, or Windows Explorer has crashed. Press Windows key + Ctrl + Shift + B to reset the graphics driver, then Windows key + P to check the projection mode. If you see a cursor, restart Windows Explorer from Task Manager.
Our step-by-step Windows 11 black screen guide covers both cases, with and without a cursor, including Safe Mode and driver rollback.
Why is my laptop battery draining so fast on Windows 11?
Fast battery drain is usually caused by high screen brightness, apps running in the background, or a process stopping the laptop from sleeping. Go to Settings > System > Power & battery and open Battery usage to see which apps use the most power. Turning on Energy saver from Quick Settings also helps.
Energy saver, introduced in Windows 11 24H2 to replace battery saver, lowers screen brightness, turns off transparency effects and limits background activity. Microsoft's Energy saver documentation lists exactly what it changes.
If the battery drops overnight while the lid is closed, check Battery usage for apps active during that time. Updating the chipset driver and BIOS from your laptop maker often improves sleep behaviour.
Why is File Explorer slow or freezing?
A slow File Explorer is often caused by a disconnected network drive, a large folder of media being scanned for thumbnails, or a cluttered Quick access history. Clear the history from Folder Options, disconnect network drives you no longer use, and restart Windows Explorer from Task Manager. Updating Windows also fixes many Explorer bugs.
- In File Explorer, select See more (the three dots) and then Options.
- On the General tab, under Privacy, select Clear.
- Right-click any mapped network drive in This PC that is no longer available and select Disconnect.
Cause and effect: File Explorer tries to reach every mapped drive and recent location when it opens. One unreachable network share can add a long delay before the window responds.
How do I find out why Windows 11 keeps crashing or restarting?
Open Reliability Monitor by running perfmon /rel to see a timeline of crashes alongside recent updates and installs. For detail, check Event Viewer > Windows Logs > System for Event ID 41 (unexpected restart) and BugCheck events, and the Application log for Event ID 1000 (app crash). The timing usually reveals the cause.
Our guide to using Event Viewer to find errors and crashes explains how to filter the logs and read these events.
If none of the fixes in this guide work, Settings > System > Recovery > Reset this PC lets you reinstall Windows while choosing to keep your personal files. Back up first, and make sure you know how your copy of Windows is activated before you start.
Frequently asked questions
Is Windows 11 26H2 more stable than older versions?
Each new version includes fixes for problems reported in earlier ones, and it receives security updates for longer. Windows 11 26H2 Home and Pro are supported until 10 October 2028. Brand-new feature updates can bring their own early bugs, which are usually fixed in the monthly cumulative updates that follow.
Will resetting Windows 11 fix most problems?
A reset fixes most software problems, because it reinstalls Windows from scratch. It will not fix failing hardware, and it removes your installed apps even when you keep your files. Try updates, driver fixes, DISM and SFC first, and the Reinstall now repair option before choosing a full reset.
Can an unactivated Windows 11 cause performance problems?
Not directly. An unactivated Windows 11 runs at the same speed, but it shows a watermark and locks personalisation settings. The bigger risk comes from unofficial activation tools and modified ISOs, which can bring malware that does slow a PC down and compromise its security.
How do I know if a problem is hardware or software?
If the problem also appears in Safe Mode, after a reset, or before Windows loads, hardware is more likely. Problems that start after an update, driver change or new app usually point to software. Reliability Monitor and Event Viewer help show which change came first.
Should I use a PC cleaner or optimiser app?
Windows 11 already includes what most cleaner apps offer: Storage Sense, startup app control in Task Manager and Windows Security. Third-party optimisers and registry cleaners can remove settings Windows needs and often push paid upgrades. Stick with the built-in tools covered in this guide.
Related guides
- Windows 11 black screen: how to fix it
- How to find, download and update drivers in Windows 11
- How to use Event Viewer to find errors and crashes
- Fix activation error 0x803FA067 after a hardware change
- How to check your Windows 11 version and update to 26H2
Links in this guide
| Link | Type | Why it helps |
|---|---|---|
| Reinstall the current version of Windows | External | Repair option that keeps apps and files |
| Energy saver in Windows 11 | External | What Energy saver changes to save battery |
| Check your Windows 11 version | Internal | Stay on a supported, patched version |
| Find and update Windows 11 drivers | Internal | Driver fixes for Wi-Fi, sound, Bluetooth and CPU issues |
| Activation error 0xC004F050 | Internal | Fixes the invalid product key error |
| Windows 11 black screen fix | Internal | Full steps for black screen problems |
| Event Viewer guide | Internal | Tracing crashes and restarts |
| Windows 11 Pro key | Internal | Genuine activation to clear the watermark |
| Windows 11 Home key | Internal | Genuine activation for Home PCs |