How to Clean Junk Files on Windows Without Slowing Down Your PC

If your Windows computer has started to feel heavy and unresponsive, chances are it’s carrying more digital clutter than it should. Over the months (or years), unused files quietly pile up in the background. These are called junk files — things like cached data, leftover installer files, or logs that served their purpose once but are now just hogging space.

The good news? You don’t need to be a tech expert to clear them out. Windows already gives you simple tools to do the job. Let me show you two reliable ways: using the built-in Disk Cleanup tool and doing a quick manual sweep of temporary files.

Method 1: Using the Disk Cleanup Tool

Every version of Windows — from XP to Windows 11 — comes with a small but mighty feature called Disk Cleanup. Think of it as the system’s in-house janitor. It knows where the clutter lives and cleans it out in a few clicks.

Why bother with Disk Cleanup?

It automatically identifies safe-to-delete files.
It can free up space without risk.
It’s much faster than digging through folders yourself.

How to Use It (Step by Step)

Find the tool – Hit Windows + S on your keyboard, type Disk Cleanup, and open it.
Choose your drive – Most of the junk sits on your C: drive (where Windows lives). Pick that and click OK.
Let Windows scan – The tool quickly checks what can go wrong. You’ll see a list: temporary files, Recycle Bin items, cached files, thumbnails, and more.
Tick the boxes – Select the categories you’re fine with deleting. Don’t worry, Disk Cleanup doesn’t show anything critical.
Delete – Click OK, then confirm. Windows will quietly sweep away the clutter.

💡 Pro tip: At the bottom of the window, there’s a button called Clean up system files. That’s where the real gold is — old Windows updates, leftover system error reports, and other hidden junk. I once recovered nearly 6GB of space just by using this option.

Method 2: Clearing Out Temporary Files Manually

Even with Disk Cleanup, some stubborn junk files stick around. That’s when it helps to take matters into your own hands. Windows keeps temporary files in a few well-known spots, and you can safely empty them.

Why do temp files exist anyway?

When apps run, they create short-term files to speed things up — like caching an image you just opened or storing installation data. The problem is, Windows rarely deletes them after they’re no longer needed. So, months later, your system may be holding thousands of files that do nothing but waste space.

How to Delete Them Manually

Open the Run box – Press Windows + R.
Type %temp% and hit Enter – A folder full of temporary files will appear.
Select everything – Press Ctrl + A, then hit Delete.
- Some files may refuse to go because they’re in use. Just skip those.
Check other folders too –
- Type temp in the Run box (without the % symbols) and repeat.
- Do the same with prefetch.

That’s it — no complicated steps. In many cases, this alone can free up a couple of gigabytes, especially if you haven’t done it in a while.

A Quick Example

Last month, I helped a friend who complained that her laptop was crawling. We opened the %temp% folder, and it had more than 45,000 files — mostly leftovers from Chrome, Zoom, and Microsoft Office. After deleting them and running Disk Cleanup, she instantly freed up 11GB of space. Her laptop booted faster, apps opened smoothly, and she didn’t need to buy an external hard drive.

Wrapping It Up

Junk files are like dust in your house. You don’t notice them day to day, but if you never clean, they pile up and make life harder. Running Disk Cleanup and occasionally clearing out temporary folders is an easy habit that can give your PC a second wind.

Do it once every few weeks, and you’ll keep your system lighter, faster, and frustration-free — no expensive upgrades required.

FAQs

Q1. Is it safe to delete everything in the Temp folder?
Yes. If a file is actively being used, Windows will stop you from deleting it. Everything else is just leftover clutter.

Q2. How often should I run Disk Cleanup?
Once a month is a good routine, but if you’re low on space, run it more often.

Q3. What happens if I delete old update files?
Nothing harmful. You just won’t be able to uninstall that specific update, but in most cases, it’s safe.

Q4. Do I need third-party tools like CCleaner?
Not necessarily. Windows’ built-in tools are usually enough for regular users.