i know it's an issue, but i couldn't find any solution on the net that works for me: in the login screen (the first page you see when you boot up your mac) on my macbook (Sierra OS), i see two users: my admin one and a 'guest' one. i want only the admin to appear so i just type the password and get in. i tried turn off all options on 'userd & groups', the 'guest user' still appeared. i tried turn off 'FileVault' and it worked, the 'guest user' disappeared. but then when i charged my MacBook it automatically encrypted it again or something and though it shows me the 'FileVault' is off, the 'guest user' reappeared and won't go. i don't know what else can i do to finally get rid of this 'guest user'. on my Mac mini everything's just fine.. help would be much appreciated!