Finding specific things

Where Docker's gigabytes actually live

Updated 2026-08-08 · 4 min read

Docker Desktop on a Mac runs a Linux VM, and that VM's entire disk is one file on yours. It grows to its configured limit and does not shrink on its own — which is how a laptop loses 60 GB to containers deleted months ago.

The file

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

Check its size:

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

du matters here: the file is sparse, so ls shows the maximum size, du the real usage. Every image you have ever pulled and every build layer lives inside it.

Reclaim from inside Docker first

docker system df
docker system prune -a --volumes

The first shows what Docker thinks it is using. The second deletes stopped containers, unused images, build cache and unattached volumes — read the warning, because --volumes removes data you may want.

Then shrink the file itself

Pruning frees space inside the VM, but the host file only shrinks if Docker Desktop supports reclaiming it. In Docker Desktop, Settings → Resources shows the virtual disk limit; reducing it forces a rebuild of the VM disk at the smaller size. The nuclear option — deleting Docker.raw with Docker quit — costs every image and volume, and Docker recreates it empty on next launch.

Why this file is invisible

It sits in ~/Library/Containers, excluded from Spotlight, inside a sandbox path no one browses. The storage pane calls it System Data. It is the single largest file on many development Macs, and most owners have never seen it listed anywhere.

A whole-disk search sorted by size surfaces it instantly — find ~ -size +20G in a terminal, or size:>20gb in an indexed search app.

Common questions

Can I delete Docker.raw directly?

Only with Docker Desktop quit, and it deletes every image, container and volume you have. Prefer docker system prune, which keeps what is in use.

Why does Docker.raw not shrink after deleting images?

It is a virtual disk. Deleting images frees space inside the VM, but the host file keeps its high-water mark until Docker reclaims or rebuilds it.