Computer out of disk space? What to check

Your computer says there is not enough space to save a file, install an update, or download an app. The first step is to find out which drive is full and what is taking up space. Then you can remove or move files safely, without deleting something the computer needs.

Windows and macOS can show how storage is being used. TooLab’s Storage Test checks disk speed, not free capacity, so use it only after you have made room and want to check how the drive performs.

Check what is using your storage

1. Open your computer’s storage overview. In Windows 11, go to Settings › System › Storage. On a Mac, go to System Settings › General › Storage.
2. Check which drive or storage category is nearly full. Look for categories such as apps, temporary files, documents, photos, videos, and system data.
3. Open the categories with the largest amounts and review the suggested files or locations. Check file names and dates before removing anything.
4. Move personal files you want to keep to an external drive or a cloud service, or delete files you no longer need. Empty the Recycle Bin in Windows or Trash on a Mac afterward, because deleted files can continue to use space until you do.
5. Once you have freed space, open the Storage Test if you also want to check disk performance. It measures speed for large files and small writes. It does not report how much space is available.

Leave room for the operating system to download updates, create temporary files, and save your work. There is no single free-space amount that suits every computer, but if the drive is almost full, make more room before installing a large update or app.

What the storage overview means

One drive is nearly full

Your files and apps may be using most of the space on that drive. On a computer with several drives, check which one holds the operating system and which one holds your personal files. Moving a large video from one folder to another on the same drive does not free space.

Temporary files take up a lot of space

Temporary files can include update files, caches, and items the system no longer needs. The operating system may offer safe cleanup options, but read the descriptions first. In particular, check whether Downloads is selected: it may contain files you still need.

Apps or games use most of the space

Large apps and games can take up many gigabytes. If you no longer use one, uninstall it through the operating system instead of deleting its folder by hand. Some launchers also let you move a game to another drive.

The system or other category looks unusually large

This category can include files that the system manages, such as caches, backups, or update data. Its size may change over time. Do not remove files from Windows or macOS system folders just because they look large. Use the cleanup options in Settings or ask a technician if the category stays unexpectedly large.

You have free space, but the computer still feels slow

A nearly full drive can make some tasks harder, but slow performance can have other causes too. After you free space, the Storage Test can show how quickly the drive handles large-file transfers and small writes. A browser test is not a complete drive health diagnosis and cannot prove that a disk is failing.

How to free space safely

1. Review the largest personal files. Sort your Downloads, Videos, and Documents folders by size, then open files before deciding whether to keep them. Move important files to another drive before deleting the original copy.
2. Empty deleted files. Check the Recycle Bin in Windows or Trash on a Mac, and empty it only after confirming there is nothing you need to restore.
3. Use the built-in cleanup options. In Windows 11, open Settings › System › Storage › Temporary files, review the list, and remove only items you recognize. On a Mac, open System Settings › General › Storage and review the recommendations and storage categories.
4. Uninstall apps you no longer use. In Windows 11, go to Settings › Apps › Installed apps and remove apps you recognize. On a Mac, review apps in Finder’s Applications folder and use the app’s uninstaller when it provides one. Avoid deleting unfamiliar system components.
5. Move large files to another location. Copy files to an external drive or a cloud service, then open the copied files to confirm they work before deleting the originals. If a cloud folder is set to keep files offline, check its sync settings before assuming that removing a local copy will free space without affecting your access.
6. Restart and check storage again. Some temporary space is reclaimed only after an update or app closes, or after the computer restarts. Reopen the storage overview to confirm that the available space changed.

When the drive may be failing

Running out of space by itself does not mean the drive is broken. Take the possibility seriously if files repeatedly disappear or become unreadable, the computer reports disk errors, or the drive disconnects unexpectedly. Back up important files as soon as you can, and avoid running repeated tests on a drive that is making unusual noises or failing to stay connected.

If the drive continues to report errors after you have backed up your files, contact the computer manufacturer or a repair shop. A speed test can help compare performance, but it cannot recover data or confirm that your files are safe.

What a browser storage test can and cannot tell you

A browser does not have permission to scan every folder on your computer and calculate all available disk space. That is why the operating system’s storage overview is the right place to find what is filling the drive. The TooLab Storage Test measures disk speed for large-file operations and small writes, which can be useful when comparing performance before and after a change.

Keep a separate backup of files you cannot replace. Free space and a good speed result are not substitutes for a backup.