How to Clean Disk on Windows & Mac

Cleaning your disk keeps your computer running smoothly and prevents “low disk space” warnings. This guide covers the built-in tools on Windows and macOS, plus a few manual steps. You don’t need any special software—just a few minutes and a bit of caution.

What You’ll Need

A Windows PC or Mac with an account that has administrator privileges
About 15 minutes of time
Optional: an external drive or cloud storage for files you want to keep but don’t need on your main disk

Step-by-Step

Check your disk space – On Windows, open File Explorer, right-click your main drive (usually C:), and select Properties. On Mac, click the Apple menu > About This Mac > Storage. This tells you how much space you’re working with.
Run the built-in cleanup tool – On Windows, type “Disk Cleanup” in the Start menu and open the app. On Mac, the built-in tool is called Storage Management; you’ll find it under About This Mac > Storage > Manage.
Select what to delete – In Disk Cleanup, check the boxes next to Temporary files, Recycle Bin, and other items you recognize. On Mac, look for recommendations like Optimize Storage, Empty Trash Automatically, and Reduce Clutter. Be careful not to delete anything you don’t understand.
Delete system files (Windows only) – In Disk Cleanup, click “Clean up system files” to see more options like Windows Update Cleanup and Previous Windows installations. These can free up a lot of space, but don’t remove them if you might need to roll back a recent update.
Empty the Recycle Bin or Trash – On Windows, right-click the Recycle Bin and choose Empty Recycle Bin. On Mac, right-click the Trash and select Empty Trash. This permanently deletes those files.
Clear browser caches – In Chrome, Firefox, or Edge, go to Settings > Privacy and Security > Clear Browsing Data. On Safari, go to Settings > Privacy > Manage Website Data. Clear cached images and files, but keep cookies if you want to stay logged in to sites.
Delete old downloads and large files – Open your Downloads folder and sort by size. Delete anything you no longer need. On Mac, you can also use the Storage Management tool to find large files and old documents.
Move files to external storage or cloud – If you have large files like videos or photos that you rarely access, move them to an external drive or upload them to a cloud service. This frees up space without losing anything.

Common Mistakes

Deleting files you don’t understand – If you’re not sure what a file or folder is, leave it alone. Deleting system files can cause problems.
Emptying the Recycle Bin before checking it – Make sure you don’t need any of those files. Once emptied, they’re gone forever.
Using third-party cleaners – Many “disk cleaner” apps are unnecessary and can be aggressive. The built-in tools are safe and effective.
Ignoring the “Clean up system files” option – This is where the biggest wins are on Windows, but many people skip it.

Tips

Run cleanup regularly – Once a month is enough for most people. Set a reminder if you tend to forget.
Use Storage Sense (Windows) – Go to Settings > System > Storage and turn on Storage Sense to automatically free up space by deleting temporary files and emptying the Recycle Bin on a schedule.
Enable Optimize Storage (Mac) – In Storage Management, turn on “Optimize Storage” to automatically remove watched movies and TV shows from Apple TV, and “Empty Trash Automatically” to delete items after 30 days.
Check for large files manually – Sometimes the biggest space hogs are old videos or disk images (like .dmg or .iso files) that you forgot about.

Troubleshooting

Disk Cleanup doesn’t open – Restart your computer and try again. If it still doesn’t work, run the System File Checker by opening Command Prompt as administrator and typing sfc /scannow.
Not enough space freed – If you’re still low on space, look for files you can move to an external drive. Also check if you have a Windows.old folder (from a major update) that can be removed via Disk Cleanup > Clean up system files.
Mac storage bar shows “Other” taking up lots of space – This often includes caches, logs, and app support files. Use a tool like DaisyDisk or GrandPerspective to see what’s actually there, but be careful deleting anything you don’t recognize.
Deleted files still show as used space – Sometimes the system needs a restart to update the storage display. If not, try running Disk Cleanup again.

Frequently Asked Questions

Is it safe to delete all temporary files?

Yes, temporary files are meant to be deleted. They’re just caches that programs use to speed up operations. The built-in cleanup tool only deletes safe-to-remove files.

How often should I clean my disk?

Once a month is a good habit. If you download a lot of files or install many programs, you might need to do it more often.

Will cleaning my disk speed up my computer?

It can, especially if your disk was nearly full. Low disk space can slow down the system because there’s not enough room for temporary files and virtual memory.

Can I recover files after emptying the Recycle Bin?

Usually not easily. Once the Recycle Bin is emptied, the space is marked as available, and the file may be overwritten. There are recovery tools, but they’re not guaranteed to work.

Do I need to clean the disk on a new computer?

No, a new computer should have plenty of space. But it’s good to start the habit early so you don’t let clutter build up.

What’s the difference between Disk Cleanup and Defragment?

Disk Cleanup removes unnecessary files. Defragmenting (on hard drives) rearranges data to make it faster to read. On modern SSDs, defragmenting is not needed and can actually reduce the drive’s lifespan.

Sources: Microsoft Support. Menus and buttons can differ slightly by version. Spotted something out of date? Tell us.