Repository is not signed in docker build

Question

I have the following Dockerfile that uses the latest Ubuntu image pulled from dockerhub:

FROM ubuntu:latest  
RUN apt-get update  && apt-get install -y           


        

Answer 1

As @Danila and @Andriy pointed out this issue can easily be fixed running:

docker image prune -f
docker container prune -f

but posting this answer, as running just one of them didn't work for me (on MacOS X) - running both however does.