Docker.raw: Why Your Mac Is Full After Prune

You ran docker system prune. Docker Desktop says the engine is clean. macOS still shows disk almost full. That is the Docker.raw (or Docker.qcow2 on older setups) virtual disk. It grows easily to 40–80 GB and does not shrink when you delete images inside Linux. Finder’s Get Info often under-reports how many APFS blocks are allocated. A disk map shows the truth.

This hits anyone running Docker Desktop on a Mac — US, UK, EU, Canada, Australia — especially on 256 GB and 512 GB laptops that also hold Xcode.

Where the file lives

Typical path:

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

Older Docker versions used Docker.qcow2. Rancher Desktop and Colima have their own disk images; the same rule applies: the Mac sees a sparse file, the VM sees a filesystem.

Why prune is not enough

Inside the VM, deleting an image frees guest blocks. The host file stays at its high-water mark unless Docker compact/reclaim runs, or you reset the disk. Apple’s Storage bar counts the host file toward System Data / Other.

What actually frees space

1. Quit Docker Desktop. Do not delete the file while the engine is running.
2. Inside Docker, remove unused images, volumes, and build cache (docker system prune -a --volumes only if you accept losing volumes).
3. Use Docker Desktop’s Troubleshoot → Clean / Purge data (wording changes by version) if the raw file is still huge.
4. Last resort: factory reset of Docker Desktop. You will re-pull images.
5. Confirm on a map that the Caution block shrank.

FreeUpMac marks Docker.raw as Caution so you do not treat it like a cache. It is the VM’s disk.

Do not rm it casually

Deleting Docker.raw while Docker is open can corrupt the VM. Deleting it while Docker is quit is equivalent to resetting the disk: containers and images are gone. That may be what you want on a laptop that only needed Docker for one project last year. It is not what you want the day before a release.

Reveal in Finder (Pro) if you need to see the date modified. If you have not opened Docker in six months, reset is usually correct.

Sparse files lie in Finder

APFS sparse files can show a small “logical” size and a large “on disk” size, or the reverse depending on the inspector. Treemap tools that use allocated size will show a giant rectangle even when ls -l looks modest. Believe the rectangle.

Combined with Xcode and snapshots

A typical full disk for a mobile-plus-backend developer:

• DerivedData 20–60 GB
• Docker.raw 20–70 GB
• Local snapshots after deleting old images
• node_modules from dead repos

Clean them in that order if you need the machine to boot comfortably tonight. Snapshots first if you just deleted Docker data and space did not return.

Colima, OrbStack, Podman

Different files, same idea. OrbStack is often smaller. Colima uses Lima disks under ~/.colima. Scan Home; the largest block with a VM-looking name is the one to treat as Caution.

After reset

Start Docker, pull only the images you use this week, and cap disk size in Docker Desktop settings if the version offers a limit. Then scan again. The Caution block should be boring.

Scan with FreeUpMac is free. Moving a selected leftover to Trash / Bin is Pro at $12.99 USD once. Do not Trash Docker.raw unless Docker is quit and you accept a reset — the Caution label is the warning.

Related: Mac storage full.

WSL myths and Linux muscle memory

On Linux, docker system prune frees the host. On a Mac, Docker is a Linux VM. Muscle memory from Ubuntu will mislead you. Compact/reset on the Mac side is the extra step. Blog posts that only show prune are incomplete for macOS.

Apple Silicon vs Intel images

After you switch from an Intel Mac to Apple Silicon, leftover amd64 images still occupy the VM disk until you remove them. docker images will show the architecture. Prune the unused arch, then reclaim on the host as above.

Kubernetes and minikube

minikube, kind, and Docker Desktop Kubernetes each have disks. Scan Home and ~/.minikube. Caution applies to those files too. Do not delete a running cluster’s disk because the map is red.

Sharing a Mac

If someone else uses Docker on the same login, reset is a social problem, not just a storage one. Ask. The Caution label is there so you pause.

Once Docker.raw is a boring size, keep a disk limit in Docker Desktop if your version has one, and scan after big Compose projects. That is the whole maintenance plan — not a subscription.