CleanLoupeTo free up space on a Mac, first find out what is actually using it (Apple menu › System Settings › General › Storage), then remove the biggest things you no longer need: old iPhone backups, large forgotten files, duplicates, and leftover installers. Empty the Trash afterwards, because nothing is freed until you do. Caches and System Data come last, since macOS manages much of that on its own.
This guide is the map. Each step below is short and points to a detailed guide for that one job, so you can go straight to the part that matches your Mac.
Step 1: Check how much space you really have
The "storage almost full" warning is worth confirming before you delete anything, because macOS counts space in more than one way.
Open System Settings › General › Storage. The bar at the top shows how much is used and by which category: Applications, Documents, Photos, iCloud Drive, Mail, Messages, System Data and so on. Below it are Apple's own Recommendations, including Store in iCloud, Optimize Storage and Empty Trash Automatically, which removes items that have sat in the Trash for more than 30 days.
Then select Macintosh HD in Finder and choose File › Get Info. The Available figure there can include space marked "purgeable", which macOS will hand back to apps when they need it. If you prefer Terminal, this gives a plain total:
df -h /
If the numbers disagree, that is normal. The difference is usually purgeable space, which is explained in what purgeable space on a Mac is.
Step 2: Find out what is taking up the space
Deleting blindly wastes time. Spend five minutes measuring first. The Storage categories with an ⓘ button let you browse and delete from inside the list. For your home folder as a whole, this Terminal command lists each top-level folder by size, smallest to largest:
du -sh ~/* 2>/dev/null | sort -h
A visual disk map makes this faster still. There are four ways to do it, from Storage settings to a sunburst chart, in what is taking up space on my Mac.
Step 3: Understand System Data before you panic
System Data (called Other in macOS 11 Big Sur and earlier) is often the largest bar, and it is the one category without a browse button. It is a catch-all: caches, logs, local Time Machine snapshots, iPhone backups, virtual machine files, developer tools and anything else macOS doesn't sort elsewhere. It is not one thing you can delete.
Shrinking it means dealing with its parts one at a time. The breakdown, and which parts are safe to touch, is in how to clear System Data on Mac.
Step 4: Clear caches only where it helps
Caches are copies of data apps keep so they don't have to fetch or rebuild it again. They are normal and they come back. Clearing ~/Library/Caches can recover space when one app's cache has grown large, but it is rarely the biggest win, and some caches hold live state for iCloud or Find My.
Measure first:
du -sh ~/Library/Caches
Which cache folders are fine to empty, which to leave, and how to handle browser caches are covered in how to clear cache on Mac.
Step 5: Delete old iPhone and iPad backups
If you ever backed up an iPhone or iPad to this Mac, the backups live in ~/Library/Application Support/MobileSync/Backup and each one can be large. Many people have backups of devices they no longer own.
The safe route is Finder: connect a device, select it in the sidebar, open the General tab and click Manage Backups. The full walkthrough, including how to decide which backup to keep, is in how to delete old iPhone backups on Mac.
Step 6: Find large and forgotten files
Big video exports, disk images, old project archives and downloaded installers are usually where real space goes. In Finder, press Command-F, set the Kind pop-up to Other › File Size and choose "is greater than". In Terminal:
find ~ -type f -size +500M 2>/dev/null
Both are explained in how to find large files on Mac. The Downloads folder is the easiest place to start: see cleaning up the Downloads folder.
Step 7: Remove true duplicates
Duplicate files pile up when you download the same attachment twice or copy a folder "just in case". Matching by name is unreliable; real duplicates have the same size and the same checksum. How to check, and which copy to keep, is in how to find duplicate files on Mac.
Step 8: Two special cases: photos and developer tools
Two groups of people run out of space for very specific reasons.
- Photo libraries. If Photos is your largest category, the answer is duplicates, screenshots, large videos and Optimize Mac Storage for iCloud Photos. See how to free up Photos storage on Mac.
- Developers. Xcode DerivedData, simulators, device support files,
node_modulesfolders and package caches can fill a disk mid-build. See how to free up disk space on a developer Mac.
Step 9: Empty the Trash
Everything above moves files to the Trash. The space returns only when you empty it: Control-click the Trash in the Dock and choose Empty Trash. Before you do, check that nothing in there is something you want back. Once the Trash is empty, Finder cannot restore those items.
Still short on space? Move things off the internal disk
If you have done all of the above and the disk is still tight, the remaining space is mostly things you want to keep. On an Apple silicon Mac you can't fit a bigger internal SSD later, so the options are to move data elsewhere:
- The Photos library. It can live on an external drive and keep syncing with iCloud Photos. See moving the Photos library to an external drive.
- Old iPhone backups. Archive them to an external drive instead of deleting them, as described in moving backups instead of deleting them.
- Video projects and old archives. Move finished projects, disk images and old zip files to an external drive formatted as APFS.
- Desktop and Documents. Turn on Desktop & Documents Folders in iCloud Drive and Optimize Mac Storage, so files you haven't opened in a while stay in iCloud. See iCloud Drive taking up space.
Before you move anything off the Mac, make sure it is backed up. An external drive that holds the only copy is one failure away from losing it.
What not to delete
A few rules keep this safe:
- Don't delete anything inside
/Systemor the hidden system folders. macOS protects most of it anyway. - Don't delete whole folders in
~/Library/Application Supportbecause of their size. They often hold your app data, not junk. - Don't delete the newest iPhone backup of a device you still use unless it is also backed up to iCloud.
- Don't chase a few hundred megabytes of caches when a single forgotten video is many gigabytes.
macOS also frees space on its own. It removes local snapshots when the disk fills, offers to store files in iCloud, and cleans up after software updates. You don't need to fight it. For a yes-or-no answer on specific folders, see what you can delete on a Mac.
By category
If one Storage category stands out, go straight to its guide:
- Mail: Mail taking up space
- Messages: Messages taking up space
- iCloud Drive: iCloud Drive taking up space
- Documents and Downloads: cleaning up the Downloads folder
- System Data: how to clear System Data
- Numbers that don't add up: why Mac storage numbers disagree
How CleanLoupe does it
CleanLoupe – Mac Cleaner is a free app that does the measuring and the sorting for you, with an undo. It is free with no subscription, trial, ads or account, and it runs on macOS 15 Sequoia or later.
Smart Scan runs several modules at once: Cleanup, Applications, Performance and My Clutter (plus Photos if you allow photo access). Its Clean button removes only Cleanup items marked Safe. Everything else waits in its own module for you to review.
Cleanup covers most of the steps above in one list. It proposes app caches in ~/Library/Caches (skipping caches that hold live state such as iCloud, Find My and Wallet), app logs, iOS update files, iPhone backups (marked Review, and only with Full Disk Access), Mail attachment copies, old installers and archives in Downloads older than 14 days, and the Trash. Separate groups cover developer tools and the caches of AI apps and code editors. Each item is labelled Safe, Review or Careful, and items written in the last hour are never preselected.
What makes it different from deleting by hand is the safety net. Files it removes go to the Trash and are recorded in History, where Put Back restores it until you empty the Trash. Protected system paths are refused outright.
What it doesn't do: it can't break System Data down into a single "delete" button, because no tool honestly can. For local snapshots you use its Performance module or tmutil, and for things like Docker volumes or virtual machines you still need the manual route.
If you uninstall apps to free space, removing an app and its leftovers covers that separately.
FAQ
What is the fastest way to free up space on a Mac?
Check Storage settings, then delete the single largest thing you don't need, which is often an old iPhone backup, a video file or an installer. Empty the Trash. That usually recovers more than any amount of cache clearing.
Is it safe to delete System Data on a Mac?
Not as a whole. System Data is a mix of caches, snapshots, backups and logs, and you can only reduce it by dealing with those parts individually. Some parts, like local snapshots, macOS removes on its own when space runs low.
Why does my Mac say storage is full when I deleted files?
Deleted files stay in the Trash until you empty it. Also, some space is shown as purgeable and macOS frees it only when needed, so the number may lag for a while. Why Mac storage numbers don't add up covers the other causes.
How much free space should a Mac have?
Apple doesn't publish a fixed number for everyday use. A practical rule of thumb, not an Apple figure: keep roughly 10 to 15% of the disk free, and never less than about 20 GB, so macOS has room for swap, caches and temporary files. Before a major macOS upgrade, check the download size in Software Update and leave plenty more than that, because the installer needs extra room to unpack. If there isn't enough, Software Update tells you, and Apple's own advice is to free up space and use Software Update, which needs less room than other install methods.
Is System Data the same as Other storage?
Yes. macOS 11 Big Sur and earlier called this category Other; macOS 12 Monterey renamed it System Data. The contents and the fixes are the same.
Does clearing cache free up a lot of space?
Sometimes, when one app's cache has grown large. Most of the time, caches are a small share of the disk and they rebuild as you use your apps.
Ready to try the scan-and-undo approach? Download CleanLoupe and run Smart Scan to see where your space has gone.