Help · Mac storage
Moving Docker to an external drive.
Docker Desktop keeps all your Linux containers and images in one large disk image file, Docker.raw. If it's taking more room than your Mac can spare, Docker has its own setting to keep it on another drive. Use that, never Finder.
Before you move it: clean up
A smaller disk image moves faster and takes less room on the drive. Run docker system df to see what's using the space. To remove what's unused, see Docker using too much disk space? It covers docker system prune (which deletes permanently) and Docker's other clean-up options.
Move the disk image with Docker's setting
- Connect the external drive.
- Open Docker Desktop and choose Settings (from the Docker menu, or the gear in the Dashboard).
- Click Resources, then Advanced.
- Under Disk image location, click Browse and choose a folder on the external drive.
- Click Apply for the change to take effect.
If the folder you pick already has a Docker disk image in it, Docker asks whether to use that one or replace it. Replacing it means losing whatever was in the old one.
These steps follow Docker's documentation as of October 2026. Labels can change between Docker Desktop versions; if yours look different, check Docker's FAQ for Mac.
Never move Docker.raw in Finder, or with a symbolic link or a general “move to external” tool. Docker warns that moving the file directly can make Docker Desktop lose track of it. Its setting is the only safe way.
Things to know
Docker's documentation doesn't cover external drives, so these are general points rather than Docker's own rules:
- Keep the drive connected. Every container and image now lives on it, so Docker needs it whenever you use Docker.
- Choose the format carefully. A drive formatted APFS, the Mac's own format, is the safest choice. Never use MS-DOS (FAT): it can't hold a file over 4 GB.
- Use a fast drive. Docker reads and writes its disk image all the time. On an older hard drive or a slow hub, builds and containers will feel sluggish, so an SSD is best.
- Back up what matters. All your containers, images and volumes are in that one file. If the drive fails or is erased, they go with it. Push images you've built to a registry, and back up the data in your volumes.
- To move it back, use the same setting and choose a folder on your Mac.
Done with Docker altogether? See how to uninstall Docker Desktop.
See how much Docker is really using.
Pangalin Space Manager finds Docker's disk image in its usual place (marked Caution, with Docker's own steps), and Where did the rest go? shows Docker's virtual machine as part of System Data, with a button to open Docker. Its Janitors can run docker system prune -f for you while Docker is running. The confirmation says plainly that it deletes permanently and that Docker does the removing; named volumes are never touched. Janitors need a licence, because the space they free can't be measured in advance. To move Docker's disk image, use Docker's own setting above.
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