firstly this is an unraid issue it is not image related, check that you are not using a specific tagged version, this can sometimes confuse the unraid webui into thinking there is an update, to do this left click krusader, select edit, the toggle 'advanced view' and check the repository, it should be 'binhex/arch-krusader', if this is ok then please post the issue at https://forums.unraid.net/forum/58-docker-engine/