Free Mac storage guide · Updated 3 October 2026
Mac startup disk almost full?
Start with files you recognise. Check how much space is available, protect anything you need, then remove one confirmed source of clutter and measure again.
By Martin R. E. Cardoso · For Apple silicon and Intel Macs
1. Find the storage view for your Mac
macOS Ventura 13 or later
Apple menu → System Settings → General → Storage.
macOS Monterey 12 or earlier
Apple menu → About This Mac → Storage.
Give the categories time to calculate. Note the available space, the largest category and the exact warning. An iCloud storage warning concerns a different storage allowance from the disk inside your Mac.
Use the same storage view for your before-and-after comparison. Write down what you were trying to do when the warning appeared: save a document, copy a video or install an update.
2. Choose a small, understandable first change
Save your work first. If a file matters, confirm you have a separate, usable backup before deleting its local copy. If this is a school or work Mac, follow your organisation’s storage and retention rules.
- Review Downloads. Look for an old installer or duplicate download you can identify. Open or inspect it before deciding that it is unnecessary.
- Inspect large personal files. A completed video export may be easier to assess than an unfamiliar system folder. Check whether the original project still depends on it.
- Use the relevant app for managed content. Remove downloaded media, old device backups or unused apps through their supported controls. Follow Apple’s specific instructions when moving a Photos library.
- Check the Bin before emptying it. Space is not released merely by moving files there. Emptying it is the irreversible step: confirm that the contents are unwanted or safely backed up.
3. Compare the result: a worked example
This is an illustrative example, not a promised amount of recovered space.
Before
A Mac shows 4 GB available. Downloads contains a recognised 8 GB duplicate video export.
One change
The owner verifies the retained copy and its backup, removes the duplicate and checks the Bin before emptying it.
After
Storage reports roughly 12 GB available. The owner retries the original save operation and records whether it works.
Available space can change while other apps are working. If the figures do not settle, save your work, restart normally and check again. Record the result before trying another change.
4. If the disk is still almost full
- System Data is the largest category: it groups files that do not fit other categories; it is not a single folder to delete. Read why System Data can be large.
- Space quickly disappears again: record the time, the change in available space and the apps or transfers running. This is more useful to support than repeating a cleanup.
- There is room, but the Mac is still slow: use the Mac performance checks to separate memory demand from storage pressure.
- You cannot identify a safe candidate: stop and ask for help. Do not experiment with unfamiliar Library or System files, erase the disk or run deletion commands copied from a forum.
Before contacting support, collect the Mac model, macOS version, available space, exact warning and changes already tried. Redact personal filenames and account details from screenshots.
Common questions
Do I need to buy a cleaner?
You can carry out these first checks using macOS and Finder. Identify the cause before deciding whether any additional tool would help.
How much space should I free?
Start with the requirement for the task that failed. An update and a small document save have different needs; a single fixed target does not suit every Mac or task.
Can I delete everything in Downloads?
No. Downloads may contain the only copy of a document or installer you need. Review files individually.
Apple’s supporting instructions
Apple: free up storage space on Mac explains the version-specific storage controls and supported ways to remove or move content.