How to delete System Data on a Mac (safely)
System Data is not a folder you can drag to the Trash. It is a storage label for many kinds of files. Here is how to shrink it without breaking macOS.
You cannot delete a “System Data folder” on a Mac, because that folder does not exist. System Data is a category in System Settings → General → Storage. Apple groups caches, logs, local iOS backups, leftovers from deleted apps, installers, virtual-machine images and Time Machine local snapshots under one grey bar. There is no single directory to remove, and there is no Delete button next to the category.
What you can do is reduce the components that feed the number. Empty the Trash,
remove old iPhone or iPad backups you no longer need, clear regenerable caches,
remove leftovers from apps you already deleted,
delete stale .dmg and .pkg installers, and — carefully —
thin local Time Machine snapshots with tmutil. Do not touch
/System, do not wipe ~/Library/Containers as a whole, and
do not delete anything you cannot identify.
For a plain-language map of what the category actually contains, read what System Data on a Mac is. For the broader storage checklist that includes Photos, Messages and Downloads, use how to free up disk space on a Mac. On one real 994 GB Mac we measured, the removable pieces inside System Data-style clutter totalled 84.8 GB.
Confirm the number before you delete anything
- Open System Settings → General → Storage.
- Wait until the coloured bar finishes calculating. On a full disk this can take a minute or two.
- Hover the grey segment labelled System Data (older macOS builds called it Other).
- Note the size. Anything from about 20 GB to 100 GB is common; above that, look for a single oversized backup or cache first.
Storage settings will not expand System Data into a file list. That is why people search for “how to delete System Data on Mac” and end up on dangerous advice that treats the category like a disposable folder. The safe approach is bucket-by-bucket cleanup of things you can name and reverse.
See what is inside your System Data free. Download Broomkit — scan forever, review every path, reclaim only when you choose.
Download FreeSafe buckets that actually reduce System Data
Work through these in order. Most Macs regain tens of gigabytes from the first three alone. Each step is reversible if you move files to the Trash and empty it only after you are sure.
1. Empty the Trash
Deleted files still occupy disk until you empty the Trash. macOS often counts that space in awkward places — including System Data — until it is gone. Right-click the Trash in the Dock and choose Empty Trash, or open the Trash and click Empty. If you use iCloud Drive with “Optimise Mac Storage”, confirm you are not emptying something you still need on another device.
2. Delete old iOS and iPadOS backups
Local device backups are one of the largest single causes of a System Data figure north of 50 GB. A full iPhone backup can exceed 100 GB. If you already back up to iCloud, the local copy on the Mac is usually redundant.
- In Finder choose Go → Go to Folder (⇧⌘G).
- Paste
~/Library/Application Support/MobileSync/Backupand press Return. - Each folder inside is one device backup. Check sizes with File → Get Info.
- Move backups you no longer need to the Trash, then empty the Trash.
You can also manage device backups from Finder when an iPhone or iPad is connected: select the device in the sidebar, open Manage Backups, and delete outdated entries. Prefer that route if you are unsure which folder maps to which device.
3. Clear regenerable caches
Application and browser caches live mostly under ~/Library/Caches and
inside sandboxed app profiles. They are designed to be rebuilt. Clearing them is the
largest safe win after backups for many people. Follow the full procedure in
how to clear cache on a Mac — quit apps
first, delete the contents of cache folders rather than the folders
themselves, and leave system paths alone.
On the reference Mac, application caches alone held about 22.5 GB, with Chrome’s cache a frequent multi-gigabyte offender. After clearing, the first launches are slightly slower while caches refill. That is expected, not a failure.
4. Remove leftovers from apps you already deleted
Dragging an app to the Trash removes the .app bundle only. Preferences,
Application Support folders, containers, logs and saved state stay in
~/Library forever. Those orphans feed System Data for years. Match them
by bundle identifier (com.vendor.appname), not by display name, and never
delete a shared vendor folder just because one app lived inside it. The complete
leftover map is in
how to uninstall apps on a Mac completely.
5. Delete old installers and disk images
Sort ~/Downloads by size. Large .dmg, .pkg and
.iso files for software you already installed are dead weight. They often
sit for months because Downloads feels “personal” rather than system — yet Storage
still folds many of them into the opaque grey bar. Keep the installer only if you still
need an offline reinstall without the App Store or a download link.
6. Thin Time Machine local snapshots (carefully)
Even without an external Time Machine disk attached, macOS keeps local snapshots for fast recovery. They count toward System Data and toward “purgeable” space. macOS is conservative about releasing them when free space is tight, which is why a Mac can look full while Apple insists space is reclaimable.
Use Terminal only if you understand the trade-off. Thinning snapshots frees space now and reduces how far back local recovery can go until new snapshots accumulate. Prefer Apple’s guidance in Free up storage space on your Mac first. When you do thin, prefer Apple’s documented approach or a bounded command such as:
tmutil thinlocalsnapshots / 21474836480 4
That asks macOS to free up to roughly 20 GB of local snapshots with urgency level 4. You will be prompted for an administrator password. Do not run destructive snapshot-delete loops copied from forums unless you know exactly which snapshot you are removing, and never disable Time Machine entirely just to chase the System Data number.
| Bucket | Typical impact | Risk if careful |
|---|---|---|
| Empty Trash | Whatever you already deleted | Low — confirm before emptying |
| iOS / iPad backups | Often 10–100+ GB each | Low if iCloud Backup covers the device |
| User caches | Often the largest regenerable slice | Low — apps rebuild caches |
| Deleted-app leftovers | Hundreds of MB to multi-GB | Low if the app is truly gone |
| Old installers | 1–5 GB common | Low — re-download if needed |
| Local TM snapshots | Varies; can be large | Medium — reduces local restore depth |
What you must never delete while “cleaning System Data”
/System and anything under the sealed system volume —
macOS itself. System Integrity Protection blocks most of this for a reason. Guides
that tell you to “delete System folders” are describing a different era of macOS or
are simply wrong.
/System/Library/Caches — kernel and system caches, not
the same as ~/Library/Caches. Removing these can leave a Mac that will
not boot cleanly.
~/Library/Containers as a whole — despite the name,
this is not disposable cache. It holds live sandboxed app data, including Notes and
other databases. Deleting a container destroys real user data. Only remove a
specific container when you know it belongs to an app you have fully abandoned, and
prefer Trash over permanent delete.
Swap files, sleep images, and random “hidden system” packs sold by junk cleaners — freeing a couple of gigabytes by breaking wake-from-sleep or forcing apps to re-download language packs is a bad trade. If a tool will not show the full path before removal, do not use it on System Data.
Also leave System (the separate Storage category for macOS itself, usually around 10–15 GB) alone. People confuse “System” with “System Data”. System is the OS. System Data is the leftovers bucket described in What is System Data on a Mac?
A practical order for a MacBook that feels full
On a MacBook Air with a 256 GB SSD, System Data in the 40–80 GB range can feel like the machine is broken. Storage is soldered, so there is no upgrade path. The cleanup order is the same as on a desktop, but the first two buckets usually matter more:
- Empty Trash.
- Remove any local iPhone or iPad backup you do not need.
- Clear user caches, largest folders first.
- Clear Downloads of old installers and disk images.
- Sweep leftovers from apps you removed months ago.
- Only then consider thinning local snapshots.
If Finder still cannot explain the missing space after those steps, you are almost certainly looking at System Data components that Storage will not list. A category scanner that shows paths — not a one-click “optimise” button — is the next useful move. That is also the point where the pillar guide free up disk space on a Mac helps: it places System Data next to Photos, Messages attachments and large old files so you do not tunnel-vision on one bar segment.
Scan free forever. Broomkit maps caches, leftovers, installers and more — then moves selected items to the Trash only when you confirm.
Download Free for MacWhy System Data grows back (and when that is fine)
Most of System Data is working data. Caches refill as you browse and open apps. Logs accumulate. Local snapshots are taken on a schedule. Clearing System Data is maintenance, not a permanent diet. A healthy Mac will always show some System Data; zero would mean the machine is not doing useful work.
What is not fine is a number that climbs without bound: an abandoned backup folder, a runaway log, a Docker or simulator image nobody uses, or leftovers from a decade of half-uninstalled apps. Those pieces do not expire on their own. Targeting them — not “deleting System Data” as a slogan — is how you keep a small SSD usable.
Purgeable space overlaps this story. Apple marks some System Data as reclaimable when the Mac is under pressure. In practice the OS is cautious, so users still need the manual buckets above. Thinning snapshots and deleting known-safe caches forces the issue without waiting for macOS to decide you are desperate enough.
How Broomkit fits — and what it will not do
Broomkit is built to show the pieces that Storage hides: caches, logs, old installers, duplicate files, iOS backups, Mail attachments, developer package caches and leftovers from deleted apps. Scanning, the Disk Map and path browsing stay free permanently. Moving selected items to the Trash (Reclaim) and the complete uninstaller unlock with a one-time licence. Everything goes to the Trash first so a mistake is recoverable until you empty it.
Broomkit will not claim to “delete System Data” with one button, because that claim is
dishonest. It will not wipe /System, and it does not invent malware
cleanups without a maintained threat feed. If you want the conceptual background
before you clean, start with
what System Data is; if you want
the whole-disk playbook, use
free up disk space on a Mac.
Related guides
Sources: Apple — Free up storage space on your Mac · Apple — Back up your iPhone or iPad · Apple — About System Integrity Protection. Published 3 September 2026. Measurements taken on macOS 26, 994 GB disk.