Mac Disk Space Helper · Help

“Your startup disk is almost full” on Mac: what it means and what to do

This warning means the drive macOS starts from has very little free space. Your Mac may still work, but saving files, installing updates, or using apps can become difficult. Start by checking how much space is available, then look for things you recognise and no longer need.

Check how much space is available

On recent macOS versions, open the Apple menu , choose System Settings, then General and Storage. On older versions, look under About This Mac and Storage. The wording and layout can vary. Give the storage categories a moment to load.

Find the folders and files worth reviewing

Mac Disk Space Helper can scan a folder you choose, such as Downloads, Documents, or a folder where you keep video projects. It shows which folders and files are largest so you can inspect them in Finder. The app reads sizes; it does not delete or move files or free space automatically.

If you are unsure where to begin, see how to find the biggest folders and files on your Mac.

Make changes only when you recognise the item

Avoid removing unfamiliar items from Library or System folders. If the warning remains and you cannot identify a safe item to review, use Apple’s storage guidance or contact Apple Support.

Review large downloads, installers, duplicate exports, or media you can replace or store elsewhere.
Check the Bin before emptying it. Items still in the Bin continue to use storage until it is emptied.
If you use iCloud or an external drive, check that important files are available where you expect before removing a local copy.
Restart after a cleanup and check Storage again. Some categories take time to update.