bug 1674765 and https://askubuntu.com/questions/92349/how-do-i-hide-a-particular-user-from-the-login-screen have information how to deal with this
bug 1674765 and https:/ /askubuntu. com/questions/ 92349/how- do-i-hide- a-particular- user-from- the-login- screen have information how to deal with this