Mac storage analyzer: what those 200 GB called "Other" really are

If you go to About This Mac → More Info → Storage, you get the bar. The famous bar. It shows colour-coded chunks for Apps, Photos, Mail, Music, Documents, System Data, macOS, and the mystery one called Other (sometimes "System" depending on macOS version).

On the machine I am writing this on, Other is 214 GB. The whole disk is 1 TB. That is a fifth of the drive devoted to a category Apple cannot or will not name.

I scanned it folder by folder so you do not have to. Here is the breakdown, in descending order of stupidity.

1. Old iOS device backups: 68 GB

The single biggest culprit. Every time you have ever plugged in an iPhone or iPad, macOS quietly made a full backup of the device and tucked it away in:

~/Library/Application Support/MobileSync/Backup/

There is no UI in macOS that warns you these exist. There is also no automatic cleanup. The backup from my old iPhone 11 from 2021 was still there.

To check what you have: Finder → press Cmd-Shift-G → paste the path above. Each subfolder is one device backup, named with an opaque hash. The folder size tells you which is which (most recent = biggest).

To clean: in Finder, do not just delete the folders. Open System Settings → General → Storage → iOS Files on macOS 13+ (or use Apple Configurator). It lists backups by device name and lets you delete cleanly. Be sure the device you are deleting a backup for has a current backup somewhere else first - iCloud or a fresher local backup.

Reclaimed: 52 GB.

2. Xcode DerivedData and simulators: 47 GB

If you have ever installed Xcode, you have these. Even if you uninstalled Xcode last year and forgot.

• ~/Library/Developer/Xcode/DerivedData/ - cached builds. Safe to delete; will be regenerated.
• ~/Library/Developer/CoreSimulator/Devices/ - simulator volumes. Each one is a complete fake-iPhone disk image.
• ~/Library/Developer/Xcode/iOS DeviceSupport/ - debugging symbols from every iOS version you have ever debugged against.

I ran xcrun simctl delete unavailable, then nuked DerivedData and the iOS DeviceSupport folders for everything older than iOS 16. Reclaimed 41 GB.

3. Docker.raw: 38 GB

Docker Desktop stores all its images and containers inside a single sparse disk image at:

~/Library/Containers/com.docker.docker/Data/vms/0/data/Docker.raw

It only grows. Even when you delete a container, the file does not shrink unless you tell Docker Desktop to compact it. On my machine it had ballooned to 38 GB.

Fix: open Docker Desktop → Settings → Resources → Advanced → "Clean / purge data". Reclaimed 31 GB.

4. Downloads folder: 22 GB

The Downloads folder is everyone\'s mess. Mine had:

• Three full Xcode installers (15 GB each, of which 12 GB had been overlapping). I had downloaded them when the machine was offline and forgotten.
• A 4 GB video I AirDropped from my phone, watched, and never deleted.
• About 300 PDFs of bank statements going back to 2019.

I sorted by size descending, sent everything over 100 MB to Trash unless I had a specific reason to keep it, and reclaimed 18 GB without even getting to the small files. The bank statements need to live somewhere, but it is not Downloads.

5. Mail attachments: 14 GB

If you use Apple Mail, it caches attachments locally for offline access. Over years, this adds up.

Mail → Settings → Accounts → pick the account → "Download Attachments" set to None. Then Mail → Mailbox menu → "Erase Junk Mail" and "Rebuild" your mailboxes. Reclaimed 9 GB.

Mail keeps the messages themselves in iCloud or on the IMAP server, so you are not losing anything - just the local cache.

6. Parallels and UTM VMs: 12 GB

A Windows VM I had not opened in nine months was sitting there at 12 GB. I exported the user folder to an external drive and deleted the VM. Reclaimed 12 GB.

Even if you use the VM regularly, you can usually compact it: in Parallels, right-click the VM → Configure → Hard Disk → Reclaim. In UTM, similar option in the disk settings.

7. Browser caches: 8 GB

Chrome, Safari, Arc, Brave - each one keeps its own cache. Most of it is small files, but there are tens of thousands of them, and they add up.

The boring fix: in each browser, settings → Privacy → Clear Browsing Data → Cached Images and Files. Reclaimed 6 GB combined.

8. Application caches in ~/Library/Caches: 6 GB

Slack, Discord, Spotify, Photoshop, and a long tail of smaller apps all park caches here. Most are harmless; the app rebuilds them when needed.

I clear caches selectively, not blanket. The big ones for me were Slack (1.4 GB), Adobe (1.1 GB across various sub-caches), and Spotify (0.9 GB).

What I left alone

A few categories of "Other" you should not touch:

• Time Machine local snapshots. They look like used space but get garbage-collected within 24 hours.
• Spotlight index (/.Spotlight-V100). Deleting it just forces a rebuild and uses your CPU for an hour for no real space gain.
• System APFS reserved blocks. Not user-touchable.
• System logs (/Library/Logs and /var/log). Usually small. Skip unless you really know what you are doing.

Total reclaimed

From 214 GB of Other, I reclaimed 169 GB in about 90 minutes. The remaining 45 GB is legitimate stuff - Time Machine snapshots, my actual VM, current Xcode dependencies for a project I am working on.

The whole exercise underlines something boring but true: "Other" is not a mystery, it is just an unhelpful label. A real disk-space analyzer that shows you folder sizes is enough to figure out where the space went. Then it is just choices about what you can stop keeping.

If you want a visual map instead of a list, the sunburst view in DiskSpace makes the biggest folders pop out instantly - the wedges scale with size, so a single 30 GB folder is impossible to miss.