'Other' storage on Mac became System Data: what changed

Part of: System Data on Mac: what is inside and how to reduce it safely (System Data)

If you remember the “Other” bar in the Mac storage view and now see “System Data”, you are looking at the same idea under a newer name. Both labels mean: everything that macOS cannot sort into Apps, Documents, Photos or media. The steps for finding space in it are the same.

What changed

Older macOS versions showed a category named Other. Newer ones show System Data instead, and the storage view is organised differently. Apple has changed the layout more than once, so a bar from an old screenshot will not look like yours.

Treat the name change as a relabel, not a new problem. The contents of each label are not identical between versions, so do not expect the same figure after an upgrade.

What the catch-all usually holds

• Caches and logs
• App support data, such as local databases and downloaded content
• Local snapshots
• The Spotlight index
• Swap and system files
• Plug-ins, fonts and installers

The System Data pillar guide explains each part and how to check it.

How to look at it

Open Apple menu > System Settings > General > Storage. Then use these read-only checks in Terminal:

du -sh ~/Library/* 2>/dev/null | sort -h | tail -5
tmutil listlocalsnapshots /
df -h /System/Volumes/Data

The first shows your biggest Library folders. The second lists snapshots. The third shows how much of the disk is in use in total.

How to read the three results

The first command sorts folder sizes from small to large and tail -5 keeps the five biggest, so the last line is your biggest Library folder. The 2>/dev/null part hides permission errors, which means protected folders may be missing from the list. For the second command, an empty result means there are no local snapshots. For the third, compare Used and Avail: if Avail is healthy, a large catch-all bar is not a problem you need to fix.

Why the figure may still look wrong

Part of what the bar shows is space macOS can free when it needs it, which is why the numbers differ between tools. See the purgeable space guide. Local snapshots are another common reason, covered in the snapshots guide.

Safe, Risky, Never

Safe

• Clearing old caches and logs of apps you can name.
• Emptying the Trash.
• Restarting so macOS recounts.

Risky

• Application Support folders.
• Snapshots you did not create.

Never

• Deleting anything inside /System or hidden system folders.
• Deleting files you cannot identify only because they are large.

Old advice that no longer fits

Some older articles tell you to remove specific hidden folders to shrink Other. That advice was written for older macOS versions. System protections are stricter today, and removing the wrong thing can break apps or the system. Prefer finding the large part first.

Why it was always hard to pin down

The old Other category and today’s System Data share the same weakness: they are defined by what they are not. Anything that is not an app, a document, a photo or a media file lands in the pile. That is why two Macs with the same disk size can show very different figures, and why a single “fix” never works for everyone.

It also explains why the figure moves for reasons that have nothing to do with you. A snapshot appears, a cache fills, an index rebuilds, and the pile grows without you adding a file.

How to read the bar without panic

A large catch-all bar is not a fault. Look at it like this:

1. Is the disk nearly full in total? Check df -h /System/Volumes/Data.
2. If yes, find the large part with the Library check above.
3. If no, a big bar is just a big bar. Leave it.

Many people see a figure of tens of gigabytes and assume something is wrong. On a Mac in daily use, caches, app data and an index add up to that quickly, and macOS frees much of it when it needs room.

Moving from an old Mac or an old guide

If you migrated from an older Mac, the new one starts with a clean slate, and System Data is often smaller at first. It then grows as you use the Mac. If you follow an older guide, check that each folder it names still exists on your version, and read what it says the folder holds before you remove anything.

For the folders you can safely reduce today, the caches guide is the best next read.

Find the space faster

DiskJoy is our product. Its scan is read-only today: it removes nothing, reports allocated bytes and gives a lower-bound reclaimable estimate. To look at your Mac in one place, run the scan.