Conflict. The container name "/web" is already in use by container "abc123"

TL;DR: A container with that name already exists. Either remove the old one (docker rm web) or start the new one with a different --name. Stopped containers keep their names, which surprises people who thought docker stop freed it.

The error

Conflict. The container name "/web" is already in use by container "abc123def456". You have to remove (or rename) that container to be able to reuse that name.

Fix it

1. See the existing container:

docker ps -a --filter "name=web" Expected: the old container, running or exited.

1. If you do not need it:

docker rm web Expected: no output.

1. Or rename instead of deleting:

docker rename web web-old

1. Re-run your original docker run --name web ....

When this applies

• Re-running a docker run --name command after the first container exited
• Scripts that do not use --rm

When this does NOT apply

• Port conflicts (different error, different fix)
• "is already in use by a network" style volume/network errors

Versions

All Docker versions.

Why it happens

Container names must be unique across all containers, including stopped ones. docker stop only stops the process; the container object (and its name) persists until docker rm.

Edge cases

• Add --rm to docker run in scripts and one-off commands so names free themselves on exit.
• A container stuck in "Removal In Progress" holds the name; restart the daemon to clear it.
• docker compose manages names itself; this error with compose usually means a stale project, fixed by docker compose down.