How to free up space on a Mac: the order that recovers the most GB with the least risk

First, see what is actually using the space

Most people start deleting before they know what is big, which is how a Sunday afternoon disappears into clearing 400 MB of screenshots while a 60 GB iPad backup sits untouched. Two minutes of looking first saves an hour.

System Settings, General, Storage. The bar at the top splits the disk into categories: Applications, Documents, Photos, iOS Files, Mail, Messages, Music Creation, System Data and so on. Each category has an (i) button that opens a list sorted by size. This view is built in and safe, and it is where most of the recommendations on this page live. Give it a minute to finish calculating; the numbers change as it scans.

Finder, sorted by size. Open a new Finder window, press Command + F, set the first condition to File Size is greater than 1 GB, and search This Mac. That finds the big individual files wherever they are: disk images in Downloads, old video exports, virtual machine disks, a forgotten 30 GB project archive. Sort the results by size with View, Sort By, Size.

Get Info on your home folder. Select your home folder in Finder, press Command + I, and compare its size with the total used on the disk. The difference is roughly what the system, apps and other users take. If your home folder is most of the disk, the rest of this page will fix it. If it is a small fraction and System Data is enormous, start with what System Data is instead.

One thing to know before you read any of those numbers: Finder, Disk Utility and the Storage pane can all disagree by tens of gigabytes. That is purgeable space, which is counted as free by some views and as used by others, and it is covered in its own section below.

Where the gigabytes usually are

Typical ranges from the kinds of Macs that show up in storage-full threads: a few years old, 256 or 512 GB, one owner, an iPhone. Your mix will differ, but the order is reliable: the top of this chart is both the biggest and the safest to clear.

Notice what is not on the chart: cache folders, log files, language files, "junk". Those are what cleaner apps advertise because they are the only things left once you have done the list above, and they are both small and self-regenerating. Our comparison of what Mac cleaners actually delete measures it.

How to free up space on a Mac, in order

Work from the top. Each step is reversible or harmless, and you can stop as soon as you have enough room. Keep at least 10 to 15 percent of the disk free when you are done; macOS needs that for swap, updates and snapshots, and below about 10 GB everything slows down.

1. Empty Downloads and the Trash

   Open Downloads in Finder, sort by size (View, Sort By, Size) and delete installers (.dmg, .pkg), expanded zip files and anything you have already moved elsewhere. Then empty the Trash: Finder menu, Empty Trash. In Finder Settings, Advanced, turn on Remove items from the Trash after 30 days so it stays empty.

2. Delete old iPhone and iPad backups

   Plug in any iPhone or iPad, select it in the Finder sidebar, click Manage Backups. Or open System Settings, General, Storage and click the (i) next to iOS Files. Delete backups for devices you no longer own and any older than the most recent one. A single backup is often 20 to 60 GB. If the device backs up to iCloud, you do not need a local copy at all.

3. Uninstall apps you do not use

   System Settings, General, Storage, click the (i) next to Applications, sort by Last Accessed. Select anything you have not opened in a year and click Delete. For apps with their own uninstaller (Adobe, Microsoft, Parallels) use it, because they store gigabytes outside the Applications folder. Dragging an app to the Trash is fine for everything else.

4. Stop Mail keeping every attachment

   Mail, Settings, Accounts, select each account, Account Information, set Download Attachments to Recent or None. Then quit and reopen Mail. Attachments stay on the mail server and download when you open the message. On an old account this alone can be 10 GB or more.

5. Turn on Optimize Mac Storage

   For iCloud Drive: System Settings, Apple ID, iCloud, Drive, turn on Optimize Mac Storage. For Photos: Photos, Settings, iCloud, Optimize Mac Storage. macOS keeps full copies of recent files locally and thumbnails of the rest, downloading originals when you open them. This can recover 50 to 200 GB on a big photo library, and the originals are still in iCloud.

6. Find the big files you forgot about

   Finder, Command + F, File Size greater than 1 GB, This Mac. Old video exports, disk images, virtual machines, archives of finished projects. Move them to an external drive or iCloud, or delete them.

7. Developers: Xcode, Docker and package caches

   Xcode keeps DerivedData, old simulators and device support files that reach 50 GB or more; delete them from Xcode, Settings, Platforms, or by removing ~/Library/Developer/Xcode/DerivedData while Xcode is closed. Docker Desktop's disk image grows and never shrinks on its own: Docker, Settings, Resources, or run docker system prune. node_modules folders in old projects add up fast; delete the ones for projects you have finished.

8. Wait a day for purgeable space to clear

   Time Machine local snapshots and iCloud's local copies are released automatically when macOS needs the room, usually within 24 hours. If the Storage pane still shows a gap between used and free after that, read the purgeable space guide before deleting anything else.

What about System Data?

Once the obvious things are gone, the Storage pane often shows one remaining giant: System Data, anywhere from 10 GB (normal) to several hundred (not). It is the category for everything macOS could not classify: caches, logs, Time Machine snapshots, Spotlight indexes, app support files, virtual machine disks that live inside app containers, and leftover installers. It is also the category every cleaner app promises to shrink, which is why people reach for one. Use the breakdown below to see what yours is probably made of before you delete anything.

The important half of the answer is that most of System Data either frees itself (snapshots, purgeable caches) or belongs to one specific app you can identify (a 40 GB Docker image, an old Parallels VM, a Final Cut render folder). The System Data guide walks through finding that app. Deleting ~/Library/Caches wholesale is the one popular step we advise against: it recovers a few gigabytes that grow back within days, and in the meantime every app rebuilds its cache from scratch, which is why Macs feel slower after a cleaner has run. The cache guide has the detail.

Why the free space numbers do not add up

At some point you will see Finder say 90 GB available, Disk Utility say 30 GB free with 60 GB purgeable, and a 10 GB file copy fail with "not enough space". All three are correct, in their own way.

Purgeable space is storage macOS is using right now but is willing to give up on demand: Time Machine's hourly local snapshots, iCloud Drive and Photos files that are also safely in the cloud, downloaded fonts and dictionaries, Safari's cached video, and app caches marked as disposable. Finder and the Storage pane count it as available because it can be. Disk Utility and some file copy operations count it as used because, at this instant, it is. The 10 GB copy fails because the purge did not happen fast enough, or because the copy checks free space before macOS has a chance to purge.

You cannot delete purgeable space directly and you should not try; it goes away on its own. What makes it go away faster: freeing real space (which lets snapshots thin), connecting a Time Machine drive and letting a backup complete (local snapshots are released once they are on the drive), and simply waiting 24 hours. tmutil listlocalsnapshots / in Terminal shows which snapshots exist; it reads only and needs no special permission. The full story, including why Disk Utility and Finder disagree, is on the purgeable space page, and Time Machine local snapshots explains the biggest contributor.

What not to delete, even when it looks big

Everything above is safe. These are the folders that show up in "free up space" guides and cause real damage.

• /System, /Library, /private, /usr, anything at the top level of the disk. macOS is on a sealed, read-only volume and will not let you, but guides that tell you to use Terminal to get round that are describing how to break your Mac.
• ~/Library/Application Support. This is where apps keep your data: mail databases, Messages history, Notes, game saves, password manager vaults, project libraries. It is large because it is important. Shrink it only through the app that owns each folder.
• ~/Library/Containers and Group Containers. Sandboxed apps' data, same as above, including the local copies of iCloud documents.
• ~/Library/Caches, wholesale. Deleting one misbehaving app's cache folder is a legitimate troubleshooting step. Deleting all of them is a slow Mac for a week and the space back within days.
• Anything inside Photos Library.photoslibrary. Open the package and delete files and you corrupt the library. Delete photos inside the Photos app, then empty its Recently Deleted album.
• Time Machine snapshots by hand. They thin themselves. If you are desperate, a completed Time Machine backup to an external drive clears them properly.
• The Mail folder in ~/Library. Change the attachment setting instead; deleting the folder deletes mail that may not be on the server.

If a guide or a cleaner wants to delete something you cannot name, the right move is to not delete it. The space you would get is small, and the thing you lose is often a database some app considers irreplaceable.

How to stop the disk filling up again

Three settings do most of the work, and they are all in places you have already visited. Finder Settings, Advanced, Remove items from the Trash after 30 days. Mail, Settings, Accounts, Download Attachments: Recent. System Settings, General, Storage, where the Recommendations section offers Store in iCloud, Optimize Storage (deletes watched TV shows and movies from the TV app) and Empty Trash Automatically with one click each.

Then two habits. Keep an external drive or a cloud folder for finished projects, and move them the day they finish rather than the day the disk fills. And once a quarter, open the Storage pane and look at the iOS Files and Applications lists; those two categories grow silently and are the easiest to trim. On a Mac that is used for development, add a monthly docker system prune and a DerivedData clear-out to the same routine.

Safe to Quit watches disk space alongside memory and heat, and tells you which process is writing the most when the free space line starts to drop, which is usually how a disk fills up overnight without anyone touching it.