This worked for me on Ubuntu 16.04 with Docker version 17.12.0-ce
Before deleting all the containers, force stop them:
$ docker ps -q -a | xargs docker stop
Then delete the containers using:
$ docker ps -q -a | xargs docker rm
Now delete all the dangling images using:
$ docker rmi $(docker images | grep “^” | awk ‘{print $3}’)