Start by finding what is taking up the most space

Before you delete anything, you need to see which files and programs are using the most storage. On Windows, open File Explorer, right-click your C: drive (or whichever drive is almost full), select Properties, and look at the pie chart. That tells you how much space is used, but not what is using it. To dig deeper, read a free tool like WizTree or Disk Usage Analyzer — both show you exactly which folders and files are the largest.

On Mac, click the Apple menu, select About This Mac, then Storage. You will see a colored bar showing what is taking up space — Photos, Documents, Applications, and so on. Click the Manage button to see a breakdown by category. This step takes five minutes and saves you from deleting the wrong thing.

Key Takeaways

  • Use a disk analyzer tool to see which files and folders are largest before you delete anything.
  • Delete old downloads, temporary files, and duplicate photos — these usually free up the most space with the least risk.
  • Uninstall programs you no longer use, especially large ones like video editors or games.
  • Move old documents, photos, and videos to an external drive or cloud storage to keep them but free up space on your computer.
  • Empty your Recycle Bin or Trash after deleting files, because deleted items still take up space until you do.

Clear out downloads, temporary files, and duplicates first

Your Downloads folder is often the easiest place to find space. Most people read files and never look at them again. Go through your Downloads folder, delete anything you no longer need, and empty the Recycle Bin (Windows) or Trash (Mac). This alone often frees up several gigabytes.

Windows also stores temporary files that pile up over time. Press Windows key + R, type %temp%, and press Enter. Select all the files in that folder (Ctrl+A) and delete them. Some files may be in use and will not delete — that is fine, just skip those. On Mac, temporary files are hidden by default, so use a cleaning tool like CleanMyMac X (paid) or Onyx (free) to safely remove them.

Duplicate photos and videos are another common culprit. If you have backed up photos to cloud storage or an external drive, look for duplicates on your main drive. Tools like Gemini Photos (Mac) or Duplicate Photo Cleaner (Windows) can find and delete duplicates automatically.

Uninstall programs you do not use

Large programs like video editing software, games, or design tools can take up 5 to 50 gigabytes each. If you have not used a program in months, uninstall it. On Windows, go to Settings > Apps > Apps & features, find the program, and click Uninstall. On Mac, open Applications, drag the program to Trash, and empty Trash.

After uninstalling, check that leftover files are gone. Some programs leave behind folders in your Documents or AppData directory. Use your disk analyzer tool to find these orphaned folders and delete them manually.

Move files to external storage or cloud backup

If you have large folders of old documents, photos, or videos that you want to keep but do not need on your computer every day, move them to an external hard drive or cloud storage. An external drive costs $50 to $150 and holds 1 to 4 terabytes. Cloud services like Google Drive, OneDrive, or Dropbox let you store files online and access them from any device, though you pay a monthly fee for large amounts of storage.

To move files safely, plug in an external drive, create a folder for your backup, and drag your old files into it. Wait for the copy to finish before deleting the originals from your computer. This way you keep the files but free up gigabytes of local space.

Check your email and messaging apps for attachments

Email clients like Outlook and Apple Mail store downloaded attachments on your hard drive, and they add up fast. Open your email program, search for messages with large attachments (Outlook: Advanced Find > Size > Large), and delete the ones you do not need. The emails themselves usually stay in your mailbox online, so you are not losing anything.

Messaging apps like Slack, Discord, and Teams also cache files and images locally. In Slack, go to Preferences > Cache and delete the cache folder. In Discord, go to User Settings > Voice & Video > Clear Cache. These caches can easily be 500 megabytes to 2 gigabytes.

Use cloud storage to sync instead of storing locally

If you use OneDrive, Google Drive, or iCloud, you can change your sync settings so files stay in the cloud and only read to your computer when you open them. On Windows with OneDrive, right-click a folder in File Explorer, select Always keep on this device or Free up space. On Mac with iCloud Drive, go to System Settings > iCloud > iCloud Drive > Options and uncheck folders you do not need locally.

This approach keeps your files accessible but does not use local storage. The trade-off is that you need an internet connection to open files that are not downloaded yet.

Add more storage if you have done all of the above

If you have deleted everything you can and your drive is still almost full, you have two options: add an external drive for ongoing storage, or replace your internal drive with a larger one. Replacing an internal drive is more involved — on a laptop it often means opening the case, and on a desktop it means reinstalling Windows or macOS. External drives are simpler and cheaper, so start there.

If your computer is a few years old and you use it heavily, adding a second internal drive (if your computer has room) or upgrading to a larger solid-state drive (SSD) can be worth the cost. SSDs are faster than older hard drives and prices have dropped significantly. A 1-terabyte SSD costs $50 to $100.

Frequently Asked Questions

Is it safe to delete files from the temp folder?

Yes. Temporary files are meant to be deleted. Windows and macOS create new ones as needed. If a program is using a temp file, Windows will not let you delete it, so you can safely try to delete everything in that folder and skip the ones that are locked.

What happens if I run out of storage completely?

Your computer will slow down significantly and may refuse to install updates or save new files. Some programs may crash. Free up at least 10 to 15 percent of your drive capacity to keep your computer running smoothly.

Should I use a cleaning tool or delete files manually?

Manual deletion is safer because you see exactly what you are removing. Cleaning tools are faster but can sometimes delete files you wanted to keep. If you use a cleaning tool, let it show you what it will delete before you confirm, and back up important files first.

Can I move my operating system to an external drive?

No. Windows and macOS must run from your internal drive. You can move documents, photos, and other personal files to external storage, but the operating system itself stays on the internal drive.

How often should I clean up my drive?

Once your drive reaches 80 percent full, start deleting old files and temporary data. If you read a lot or take many photos, do this every month or two. If you use your computer lightly, once or twice a year is usually enough.