How to Free Up Disk Space on a Mac: A Practical Checklist
"Your startup disk is almost full" tends to arrive at the worst moment: halfway through a video export, or just as a macOS update refuses to install. The good news is that most Macs have plenty of space to reclaim. The bad news is that the biggest chunks are rarely the files you'd think of, so deleting a few old documents won't get you far.
This checklist goes from the quickest wins to the deeper cleanup, so you can stop as soon as you've freed enough.
Quick answer: Open System Settings → General → Storage to see what's using space and turn on Apple's recommendations (Store in iCloud, Optimize Storage, Empty Trash Automatically). Then empty the Trash, clear out Downloads, delete old iPhone and iPad backups, uninstall apps you don't use, and remove large files you no longer need. If System Data is still huge, clear caches and Time Machine local snapshots. Aim to keep at least 10–15% of your disk free. To see all of this in one place, MacCove Space scans the whole disk and groups what's reclaimable by category.
How much free space does a Mac need?
Apple doesn't publish a single number, but two practical thresholds matter:
| Situation | Free space to aim for | Why |
|---|---|---|
| Day-to-day use | 10–15% of the disk (25–75GB on most Macs) | macOS uses free space for swap, caches and snapshots; when it runs out, everything slows down |
| Installing a major macOS update | 30–50GB | The installer needs room to download, unpack and keep a snapshot |
| Video, photo or music projects | Much more | Render files and previews can be larger than the project itself |
When the disk gets close to full, apps start to beachball, saves can fail, and updates won't install. It's worth fixing before you hit that point. If your Mac is already slow, see why your Mac is running slow.
Step 1: See where your space is going
Open System Settings → General → Storage and wait for the bar to finish calculating. Hover over each coloured segment to see how big it is. Below the bar, categories with an ⓘ button (Applications, Documents, Messages, Music Creation, TV, Trash and others) open a list you can review and delete from.
One warning: Storage settings is a rough estimate, and System Data in particular can be wildly off. Use it to find the big categories, not as an exact measurement.
Step 2: Turn on Apple's built-in recommendations
At the top of the Storage page, Apple offers a few one-click options:
| Recommendation | What it does | Worth it? |
|---|---|---|
| Store in iCloud | Keeps Desktop, Documents, Photos and Messages in iCloud, with only recent files stored on the Mac | Yes, if you pay for enough iCloud storage |
| Optimize Storage | Removes Apple TV films and shows you've watched, keeps only recent email attachments | Yes, for most people |
| Empty Trash Automatically | Deletes items that have been in the Trash for over 30 days | Yes |
Step 3: The quick wins
These take a few minutes and often free tens of gigabytes:
Empty the Trash. Files in the Trash still take up space. Also check the Trash in Photos (Recently Deleted) and Mail.
Clear out Downloads. Sort by Size in Finder (List view, then ⌘J → Calculate all sizes). Old installers (.dmg and .pkg files) are safe to delete once the app is installed.
Delete old iPhone and iPad backups. In Finder, select a device, then General → Manage Backups. Backups for phones you no longer own are pure waste, and each can be tens of gigabytes.
Remove old macOS installers. Look in Applications for anything called Install macOS....
Delete watched downloads in the TV, Podcasts and Music apps.
Step 4: Uninstall apps you don't use
In Storage settings, click the ⓘ next to Applications to see your apps sorted by size, with the date each was last opened. Anything you haven't opened in a year is a good candidate.
Remember that the app itself is often the small part. Its caches, support files and downloaded content in your Library folder can be several times bigger, and they stay behind when you drag the app to the Trash. Our guide on how to uninstall apps on a Mac completely covers where those files live.
Step 5: Find large files
Large files you've forgotten about, like old screen recordings, exported videos, disk images and virtual machines, are easy to find once you know how:
Finder search: open a Finder window, press ⌘F, click the first criterion (Kind), choose Other…, tick File Size, then set is greater than 1 GB.
Storage settings: click the ⓘ next to Documents to see large files sorted by size.
Terminal: find ~ -type f -size +1G 2>/dev/null lists every file over 1GB in your home folder.
Before deleting anything big, check it isn't something like a Photos library, a virtual machine you still use, or a project archive you'd regret losing. Move it to an external drive if you're unsure.
Step 6: Photos, Messages and Mail
Apple's own apps hold some of the biggest hidden storage on a Mac:
| App | How to reclaim space |
|---|---|
| Photos | Turn on |
| Messages | Messages → Settings → General → Keep messages: |
| Mailbox → Erase Deleted Items |
When Photos merges duplicates, the extra copies go to Recently Deleted for 30 days, so empty that album to get the space back.
Step 7: Duplicate files outside Photos
macOS has no built-in duplicate finder for regular files. Copies tend to pile up in Downloads ("report (1).pdf", "report (2).pdf"), in project folders, and when you copy files back from old drives. You can hunt for them by sorting folders by name and size, but on a full disk it's slow going. This is one of the areas where a dedicated tool earns its keep: MacCove Space finds identical files even when they have different names and live in different folders.
Step 8: Tackle System Data
If you've done all of the above and System Data is still enormous, it's usually caches, Time Machine local snapshots, developer files (Xcode, Docker) and leftovers from deleted apps. These need a little more care, so they have their own guide: how to clear System Data on a Mac. For caches specifically, see how to clear cache on a Mac.
The faster way
Going through these eight steps by hand works, and you learn a lot about your Mac along the way. But most of the effort goes into finding things, not deleting them. MacCove Space's Tachyon Scan maps the whole disk into categories (caches, logs, developer data, app leftovers, Downloads and Trash, duplicates, large and old files), shows how much each one takes, and pre-selects only items graded Safe. You review the list and clean in one step, entirely on your Mac.
FAQs
Why is my Mac storage full when I don't have many files?
Usually because of things you didn't create yourself: System Data, caches, iPhone backups, Photos and Messages attachments, and leftovers from old apps. Storage settings shows them as categories, but Finder doesn't show most of them at all.
Does moving files to iCloud free up space on my Mac?
Only if Optimize Mac Storage (for iCloud Drive) or Store in iCloud is on. Then macOS keeps recent files locally and removes older ones from the Mac, downloading them again when you open them. Without it, iCloud Drive keeps a full copy on your Mac.
Is it safe to delete files in the Library folder?
Some of them. Caches and leftovers from apps you've uninstalled are generally safe. Application Support folders for apps you still use, Group Containers and anything in /System are not. When in doubt, move items to the Trash rather than deleting them permanently, and empty it after a few days of normal use.
Should I buy an external drive instead?
For archives, old projects and media libraries, yes. External SSDs are cheap and fast. Just don't move your apps or system files there, and keep a backup.
How do I stop my Mac filling up again?
Keep Empty Trash Automatically on, set Messages to keep messages for a year rather than forever, uninstall apps you've finished with properly, and check Storage settings every few months.
Related guides
How to Clear System Data on a Mac
How to Clear Cache on a Mac
How to Uninstall Apps on a Mac Completely