Guide

What "Other" storage on Mac actually is

"Other" is not a category. It is the leftover — everything macOS could not file under Applications, Photos, Music or Documents. Newer versions of macOS renamed it System Data, which is more honest but no more specific.

Why Finder will not itemise it

Storage in About This Mac is built from a small set of known categories. Anything that does not match one of them is added to the remainder, which older macOS labels Other and macOS Ventura and later label System Data. The label changed; the contents did not. It also moves on its own, because local snapshots and iCloud placeholders appear and vanish while you watch — which is why the figure you saw yesterday rarely matches today.

What is usually inside it

  • Caches and logs from apps, plus the system caches macOS rebuilds on demand.
  • Disk images and installers — every .dmg, .pkg and .xip you kept after installing something once.
  • iOS and iPadOS device backups, several gigabytes each and easy to forget.
  • Time Machine local snapshots, which live on your startup disk, not on the backup drive.
  • Developer data: Xcode DerivedData, archives, device support and simulator runtimes.
  • Fonts, plug-ins, application support folders and mail attachments.
  • The sealed system files and other users’ data that macOS counts but will not let any app read.

How to clear it without breaking anything

01
Measure it before you touch it Other is a subtraction, so you cannot clear it from the bar chart. Measure the volume folder by folder and the same bytes turn into rows with names you recognise.
02
Start with installers and disk images If the app is already in Applications, its installer is dead weight. Superseded macOS installers are the worst offenders at several gigabytes each.
03
Delete device backups you no longer need Keep the most recent backup of a device you still own. Backups of devices you sold years ago are pure ballast.
04
Clear caches you can rebuild Caches are designed to come back. Removing them is safe; the next launch of those apps is just slightly slower.
05
Leave the sealed remainder alone Whatever is left after those cuts is mostly system files, other accounts and private app data. No app is allowed to remove it, and any app claiming otherwise is overreaching.

How Sift reports the same bytes

Sift measures the volume byte by byte and splits the leftover into rows you can act on — backups, caches, disk images, developer data — plus one hatched row for what macOS keeps private. The hatched bytes stay in the totals so the number still matches Finder instead of quietly disappearing. Scanning is free; moving a row to the Trash is part of the yearly plan.

See what your leftover really is — scanning is free

Common questions

Is "Other" storage the same as System Data?

Effectively yes. macOS Ventura and later renamed the category to System Data. Both are the remainder after the named categories are counted, so the same caches, backups, snapshots and sealed system files sit inside.

Why is my Other storage 100 GB or more?

Usually one heavy contributor rather than many small ones: Xcode data on a developer Mac, iOS backups, a pile of old installers, or Time Machine local snapshots after a long stretch without a backup drive attached. Measuring tells you which one it is in a single pass.

Can I just delete Other storage on Mac?

There is nothing to delete — it is not a folder. You clear it by removing the real files that fall into it, and part of it cannot be removed at all because macOS seals it. That is why the number never drops to zero.