It is not junk, and it is not a folder you can open. “Other Volumes” is space held by other disk volumes — and once you know which ones, the category usually explains itself.
macOS Storage settings reports space for your startup disk by category. Anything it cannot attribute to Photos, Apps, Documents, or System Data gets filed under Other Volumes. In practice that means one of a few concrete things: a second APFS volume in the same container, a local Time Machine snapshot, a mounted disk image, or a volume belonging to another macOS installation or a virtual machine.
There is no “delete Other Volumes” button, and there shouldn't be — the category is a label for several unrelated things, some of which are load-bearing.
| Source | How to confirm | What to do |
|---|---|---|
| Local Time Machine snapshots | tmutil listlocalsnapshots / | Thin them — they are recovery points, not backups |
| Extra APFS volumes | diskutil list, or Disk Utility | Delete only if you know what created them |
| Mounted disk images (.dmg) | Finder sidebar, or hdiutil info | Eject — then delete the .dmg if unused |
| A second macOS install | Disk Utility volume list | Remove via Disk Utility if you no longer boot it |
| VM disk images | Parallels / VMware / UTM settings | Shrink inside the VM tool, or archive the VM |
The most common reason Other Volumes stays put after you delete files is local Time Machine snapshots. When a Time Machine destination is unavailable — a laptop away from its backup disk, for instance — macOS keeps hourly snapshots on the internal disk instead. They look like free space to the file system and like used space to Storage settings.
Deleting your own files does nothing to them, because the snapshot is a point-in-time record that still references the old blocks. The fix is to thin the snapshots:
tmutil listlocalsnapshots / shows them. sudo tmutil deletelocalsnapshots / removes all local snapshots on the boot volume, and macOS starts fresh. On a current macOS release the system manages these automatically under disk pressure, but a machine that has not been near its backup disk for months can accumulate a surprising amount.
If the number is large, that is not corruption — it is Time Machine doing what it is designed to do. Deleting them costs you local recovery points, not your actual backups. Your external Time Machine disk is untouched.
Storage settings will not break the category down, so use the tools that will:
diskutil list — the same information as text, and easier to copy when you want to check what something is.A container is not the same as a volume. APFS shares free space between volumes in one container, so a container can show most of the disk while each volume inside it holds far less. Deleting the container deletes every volume in it — check before you act.
On a modern Mac your startup disk is split into a read-only System volume and a writable Data volume. The Data volume holds your files and is the one macOS is running from. It may appear in the volume list, and it is not spare. Similarly, do not delete a Recovery volume.
Safe candidates are volumes you can positively identify as belonging to something you no longer use: an old macOS installation, a VM you have archived, a test volume you made yourself.
No. System Data is Apple's catch-all for files on the volume you boot from. Other Volumes is space on other volumes entirely. They frequently grow for different reasons, and a fix for one will not touch the other.
Only if you know what created it. Erasing a volume in the APFS container your Mac boots from can remove snapshots, a second installation, or the Data volume itself. Confirm with diskutil list first, and prefer Disk Utility so you see what you are selecting.
Not always. APFS reclaims space when the last reference to a block disappears, so after deleting snapshots or a volume it can take a short while — and a restart — before Storage settings agrees with reality.
Trust Disk Utility and a disk-space analyzer. Storage settings rounds, groups, and sometimes counts snapshots and purgeable space that Disk Utility reports differently. When they disagree, the lower number is normally the real occupied space.
Massive Disk is a native Apple Silicon app that maps every byte of your storage across six visualizations — so an anonymous category becomes a path you can open — then gives you safe, reversible ways to get space back. Scanning is free forever; cleanup tools are Pro.