I just noticed this after upgrading to High Sierra. When I restart my MacBook, I am presented with my login as usual, but I notice there are 2 additional accounts, both of them are Guest. The first Guest account requires password to login, in which I do not know what the password is (even my own password does not work). The second Guest account is the Safari-mode only account. I have disabled the Guest account at Users & Group, unchecked Allow guests to login and uncheck Allow guest users to connect to shared folder. I do not have Find My Mac set up. Yet, both Guest accounts above still appear everytime I restart my MacBook. What suspicious is the Guest account with the password. Is it possible that I got malware, virus etc? I attach picture of the login screen.