What is “Other” storage on Mac?
“Other” storage on Mac was the old name for what Apple now calls System Data: the same catch-all of caches, logs, snapshots, and backups. Here's what changed.
If you're hunting for the "Other" category in your Mac's storage bar and can't find it, you're not losing it. Apple renamed the thing. On older macOS, "Other" storage on Mac was the fat grey catch-all slice in About This Mac → Storage. Around macOS Monterey it became System Data. Same idea, new name.
Where "Other" storage on Mac went
On macOS Sierra through Big Sur, you'd open the Apple menu → About This Mac → Storage and see the usual categories (Apps, Documents, Photos, Mail) plus a big grey block simply labeled Other. That was everything macOS couldn't sort cleanly into a named category.
Starting with macOS Monterey (12), Apple reorganized those categories and replaced much of the "Other" terminology with System Data, while also splitting out a separate macOS category for the operating-system files themselves (Macworld). The location moved too: on Ventura and later, you'll find it under System Settings → General → Storage, not About This Mac.
Same idea, new name, with one honest caveat
Two things are worth being straight about.
First, there is no single Apple document that says "we renamed Other to System Data." The rename is well-attested across reputable Mac sites and it matches the UI change you can see with your own eyes, but it's inference from the evidence, not an official announcement. Treat it as widely reported rather than gospel.
Second, don't assume the two are byte-for-byte identical. Because Monterey also carved out that separate "macOS" category, the buckets aren't a clean 1:1 swap. The safe framing is simple. The miscellaneous catch-all that used to read "Other" now reads "System Data." Same job under a new label, with the edges slightly reshuffled.
None of this changes what the category is for. Whether your Mac calls it "Other" or "System Data," it's the same grey slice that grows without asking and won't tell you what's inside, which is exactly why people keep searching for it under both names years after the rename. If you're on an older release still showing "Other," everything below applies to you too; the label is the only thing that's different.
What actually lives in "Other" / System Data
Whatever it's called, the contents are roughly the same residual pile of files that don't belong to any tidy category:
- Caches: browser and app caches in
~/Library/Cachesthat grow as you browse and build. - Logs: diagnostic and history logs macOS trims on its own schedule.
- APFS / Time Machine local snapshots: retained filesystem state that can quietly grow large.
- iOS / iPadOS device backups: stored at
~/Library/Application Support/MobileSync/Backup/, often tens of GB each. - App support data: the bulk of per-app files in
~/Library/Application Support, frequently left behind after you delete an app. - Fonts, plug-ins, and extensions: smaller, but they count here too.
- Developer files: Xcode caches, simulators, Docker's virtual disk, and package-manager caches.
One thing worth knowing: this isn't a real folder you can open. It's a rough estimate, a residual category macOS assembles, and Apple tells you outright that "you can't directly manage the contents of this category." That's why deleting it isn't a thing; you deal with the pieces inside it instead.
On newer macOS, read this instead
If you're on Ventura, Sonoma, Sequoia, or later, the category staring back at you is System Data, and that's where the actual how-to-shrink work lives. Rather than duplicate it here, the full walkthrough is the canonical guide: what is System Data covers what's inside, what's safe to remove, and what macOS clears on its own.
If your real question is bigger than one category (why the whole bar looks jammed), start with why your Mac storage looks full. And when you're ready to actually reclaim space, how to free up space on Mac ranks the wins by safety and payoff.
The frustrating part of both "Other" and "System Data" is the same. macOS shows you a number and no way to see inside it. Plumby names what's in that catch-all with exact paths (the cache folders, the old iOS backups, the snapshots), measuring each one as it goes, and it never touches your documents, photos, or projects.
