Mac storage has a habit of disappearing slowly then all at once. One day the disk is half full; the next, Xcode refuses to update, Final Cut won't render, and the system is paging like mad. The culprits are usually predictable — and the built-in tools in macOS Sequoia find them without any third-party software.
What changed in 2026
- macOS Sequoia refined the Storage Management pane. It now shows a "System Data" breakdown that includes caches, logs, and language files — the category that previously confused everyone.
- Xcode 16+ simulator runtimes grew again. A full iOS + watchOS + visionOS install is 35–60 GB. If you are not actively testing on those platforms, delete unused runtimes.
- iCloud Drive "Optimise Mac Storage" is more aggressive. Files not opened in 30 days are offloaded automatically on low-storage Macs running Sequoia.
- APFS snapshots (Time Machine local) still silently consume space. macOS removes them automatically, but you can delete them manually to reclaim space instantly.
Step 1: Start with the built-in tool
Apple menu → About This Mac → Storage → Manage (or System Settings → General → Storage on macOS Ventura+).
This opens the Storage Management pane. Key categories to check:
| Category |
Common culprit |
| Applications |
Old apps you never open |
| Developer |
Xcode simulators, derived data |
| Documents |
Downloads folder, large files |
| Mail |
Email attachments |
| System Data |
Caches, logs, language files |
| iCloud Drive |
Locally synced files |
Click each category to see what is taking space and remove it.
Step 2: Empty Trash and Downloads
Right-click the Trash in the Dock → Empty Trash. Then open Finder → Downloads and sort by size. Delete installers (.dmg, .pkg files) you no longer need — these accumulate quickly and are easily re-downloaded.
Step 3: Delete Xcode clutter (developers)
If Xcode is installed, open it → Preferences → Platforms → delete simulator runtimes you do not need. For derived data and device support:
Open Terminal and run:
xcrun simctl delete unavailable
rm -rf ~/Library/Developer/Xcode/DerivedData
rm -rf ~/Library/Developer/Xcode/Archives
These two directories often hold 10–40 GB. DerivedData rebuilds automatically on next build.
Step 4: Clear application caches
macOS caches live in ~/Library/Caches. The safest approach: open Finder → Go menu → Go to Folder → type ~/Library/Caches → sort by size → delete folders for apps you recognise (not system folders like com.apple.* unless you know what they are).
Typical large caches: Xcode, Spotify (offline songs), Slack (media cache), browsers.
To clear browser cache specifically:
- Safari: Settings → Privacy → Manage Website Data → Remove All
- Chrome: Settings → Privacy → Clear browsing data → Cached images and files
Step 5: Remove old iOS / iPhone backups
In macOS Ventura+: Finder → select your iPhone from the sidebar when connected → Manage Backups. Delete old or redundant backups. Each backup can be 3–15 GB.
Step 6: Enable Optimise Storage
Storage Management pane → Optimise Storage → Turn On. macOS offloads iTunes/Apple TV purchases and other rarely accessed files to iCloud, keeping only the most recent items local. Files remain available and download on demand.
Step 7: Delete APFS local snapshots
Time Machine creates local snapshots even when no drive is connected. To remove them:
Open Terminal:
tmutil listlocalsnapshots /
Then delete each one:
tmutil deletelocalsnapshots <snapshot-date>
Or to delete all: tmutil deletelocalsnapshots / 2>/dev/null
This can recover 5–20 GB immediately.
How to pick your approach
- Casually low on space? → Empty Trash + clear Downloads → done in 5 minutes.
- Developer running out? → Delete Xcode simulators and DerivedData first.
- Storage stuck at "System Data is large"? → Clear caches and APFS snapshots.
- Chronically low on a small SSD? → Enable Optimise Storage + move large media to external drive.
Common mistakes
Buying a third-party cleaner. CleanMyMac, MacKeeper, and similar apps charge $30–$60/year to do what the built-in Storage Management pane does for free. Some have had privacy concerns.
Deleting files in /Library (system level). Stick to ~/Library (your user library). Deleting system library files breaks things.
Expecting cache cleaning to free huge amounts. Caches typically hold 1–5 GB. If you need 30 GB, the win is in Xcode, iOS backups, downloads, and large media files.
Ignoring the "Other" / "System Data" category. This is where language files, logs, and browser data hide. It is navigable with the built-in tool.
What to skip
- CCleaner for Mac or MacKeeper — built-in tools are genuinely better.
- Manually editing plist files to clear system preferences — the risk is not worth the space.
- Deleting all
~/Library/Caches — some caches (like Mail's) need to be managed through the app or the storage pane, not a bulk delete.
FAQ
Why does System Data keep growing?
System Data includes Time Machine snapshots, caches, and logs. Delete APFS snapshots and clear app caches to shrink it.
Is it safe to delete DerivedData?
Yes. Xcode rebuilds it on next build. The only cost is longer compile times the first time.
Should I use iCloud Optimise Storage?
Yes, if you are on a MacBook with 256 GB or less. It keeps frequently used files local and offloads the rest.
What is the fastest 5-minute cleanup?
Empty Trash → sort Downloads by size and delete installers → clear Chrome/Safari cache. Usually 3–8 GB recovered.
Where to go next