For big images, it is possible to have broken pulls (partially downloaded images). It takes space and is better to clean. Docker does not show such pulls. So there is no way to remove them. I did some googling but couldn’t find any way to either show or remove broken downloads without affecting existing work (eg. reinstall Docker). Hopefully it could become a future feature.
Try the docker system prune command.
Details are here -> https://docs.docker.com/engine/reference/commandline/system_prune/
Thanks Gary for the feedback. I tried to pull an image. I saw some “Download complete” during the pulling (probably parts of the images). It stopped after many “Retrying” and finally “connection time out”. The command “system prune” couldn’t find the broken downloads. It seems it only deleted some stopped containers, according to the screen information.