Cannot delete docker image

Question

While setting up a new build machine (CentOS 7, Docker CE 17.12.0-ce), I did a simple test:

docker run -it --rm ubuntu bash

Which worked fine,

Answer 1

You could force-remove it

docker rmi [IMAGE ID] -f or docker rmi [IMAGE ID] --force

Answer 2

While setting up this system I had originally installed an old version of docker available from the standard CentOS repositories (yum install centos) instead of adding the docker repositories and installing docker-ce. Even though I'm on the latest version now, the old one must have introduced some bad data in /var/lib/docker before I upgraded. In the end I just deleted all the local image and container data and started over:

sudo systemctl stop docker
sudo rm -rf /var/lib/docker
sudo systemctl start docker

Everything is working normally now.