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Windows 11 Slow After Update? Fix It Yourself

📅 14 July 2026 ⏱ 4 min read 🔧 PC Repair

Why Your PC Slows Down After a Windows Update

You leave your PC to update overnight, come back in the morning, and it feels like you're working on a machine from 2005. You're not imagining it — and you're not alone. This is one of the most common complaints we hear from residents and expats across the Costa Blanca.

The good news: most of the time, it fixes itself within 24–48 hours as Windows finishes background indexing and configuration tasks. The bad news: sometimes it doesn't, and you need to give it a nudge. Here's exactly what to do, in plain language.

Step 1: Wait — But Not Too Long

Straight after a major update, Windows runs a process called SFC (System File Checker) and rebuilds its search index in the background. Your disk and CPU will be working hard even when you're not doing anything. Give it a full hour after the restart before you panic.

If the machine is still sluggish after an hour — or the next day — move on to the steps below.

Step 2: Check What's Hogging Your PC

Press Ctrl + Shift + Esc to open Task Manager. Click the CPU column to sort by usage. Look for anything eating 30 % or more when you're not actively doing anything. The usual suspects after an update are:

If any of these are the culprit, they'll finish on their own. Give them time. If it's something unfamiliar sitting at high CPU, that's worth investigating further — it could be a security issue worth checking.

Dusty laptop vent causing overheating after Windows update

Step 3: Restart (Properly)

"Restart" and "Shut down" are not the same in Windows 11. Shut down uses a feature called Fast Startup, which doesn't fully clear memory. A proper Restart does. Click Start → Power → Restart (not Shut down). This alone resolves the slowdown in a surprising number of cases.

Step 4: Disable Startup Apps You Don't Need

Updates sometimes re-enable programmes to launch at startup that you'd previously turned off. In Task Manager, click the Startup apps tab. Right-click anything you don't need immediately on boot — things like Spotify, OneDrive, Teams, Zoom — and choose Disable. You're not uninstalling them; just stopping them from loading the moment you log in.

Windows Task Manager showing high CPU usage after update

Step 5: Run the Windows Update Troubleshooter

Go to Settings → System → Troubleshoot → Other troubleshooters and run Windows Update. It sounds basic, but it catches and repairs broken or incomplete update files surprisingly often. It's the digital equivalent of tightening a loose cable.

Step 6: Check Your Storage

Windows 11 needs at least 10–15 % of your drive free to breathe. Updates drop temporary files that sometimes don't clean up automatically. Go to Settings → System → Storage → Temporary files and delete what Windows flags as safe to remove. If your C: drive is over 85 % full, that alone can cause serious slowdowns.

Step 7: Check for a Pending Driver Update

Sometimes a Windows update replaces a graphics or chipset driver with a generic version that doesn't perform well. Open Device Manager (right-click the Start button), look for any yellow warning triangles, and update or roll back the affected driver. Graphics drivers are the most common culprit.

When DIY Isn't Enough

If you've worked through all of the above and your PC is still slow, there are a few deeper causes that are harder to fix without experience:

These are fixable, but they're not ten-minute jobs. If you're in Pilar de la Horadada, Orihuela Costa, or anywhere on the southern Costa Blanca, bring it in or drop us a message — we'll tell you honestly what it needs.

Person using a laptop outdoors on the Costa Blanca after fixing Windows slowdown

Quick Summary: What to Try First

ProblemFixTime needed
Just updated, everything slowWait 1–2 hours, then Restart5 min
High CPU in Task ManagerIdentify the process, let it finish10 min
Slow startupDisable unnecessary startup apps5 min
Disk almost fullDelete temporary files in Storage settings5 min
Still slow after all the aboveBook a diagnostic — hardware may need attention—

FAQ

How long does Windows 11 stay slow after an update?

Usually 30 minutes to 2 hours while background tasks finish. If it's still sluggish after a day, something needs attention — follow the steps above.

Why does my PC feel slower after every Windows update?

Updates add new features, drivers, and security layers. If your hardware is ageing — especially if you have an old hard drive or less than 8 GB of RAM — each update pushes it a little harder. At some point, a hardware upgrade is the real fix.

Is it safe to turn off Windows Update to stop this happening?

We'd strongly advise against it. Updates contain important security patches. Delaying them briefly is fine; disabling them permanently leaves your PC exposed to serious threats.

Can I fix a slow Windows 11 PC myself without a technician?

Yes, in many cases — the steps in this post cover the most common causes. If they don't resolve it, the issue is usually hardware (RAM, hard drive) or a corrupted update, and a technician can sort it quickly.

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Photos via Pexels