Recently my Ubuntu 16.04 starts to boot each time without asking me to log in. I would like to enforce entering password before starting every session, how to do this?
Edit: In the System settings -> User Accounts there is no way to (un)set auto-login:

Edit2: I apparently do not belong to user group nopasswdlogin. I checked it typing groups into console, the result is: adm cdrom sudo dip plugdev lpadmin sambashare docker
Edit3: It seems that the problem doesn't occur any more. Maybe some system updates fixed it?


