How to fix Error response from daemon: Conflict. The container name '/mycontainer' is already in use by container in Docker

First, check which containers exist on your system, including stopped ones:

docker ps -a

This shows all containers with their names, IDs, and current status. Look for the container name mentioned in your error message.

Example output:

CONTAINER ID   IMAGE     COMMAND   CREATED        STATUS                    NAMES
abc123def456   nginx     ...       2 hours ago    Exited (0) 2 hours ago    mycontainer

Once you've identified the conflicting container, remove it by name or ID:

docker rm mycontainer

Or using the container ID:

docker rm abc123def456

If the container is still running, you need to stop it first:

docker stop mycontainer
docker rm mycontainer

Or force remove it in one command (stops and removes):

docker rm -f mycontainer

After removal, you can create a new container with that name.

If you want to reuse the existing container rather than create a new one:

docker start mycontainer

This is useful when:
- The container has the configuration you need
- You want to preserve volumes and state
- You're just restarting after a system reboot

To check if the container started successfully:

docker ps

You can avoid the conflict by choosing a different name:

docker run --name mycontainer-2 nginx

Or omit the --name flag entirely - Docker will assign a random name:

docker run nginx

Docker generates names like "quirky_einstein" or "elegant_turing" automatically.

If you're running temporary or one-off containers, use the --rm flag to automatically remove the container when it stops:

docker run --rm --name mycontainer nginx

This prevents name conflicts on subsequent runs and keeps your system clean. Perfect for:
- Test runs
- One-time scripts
- Development containers that don't need persistence