I suspect your Mark account is in the "nopasswdlogin" group. This means login can be done without a password being asked.
You can fix this from the command line: $ sudo deluser mark nopasswdlogin If this is the case I'm not sure what has gone wrong but that user should have been removed from that group when the password was set. It may also be fixed if you change your password using the user accounts settings. ** Changed in: lightdm (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to lightdm in Ubuntu. https://bugs.launchpad.net/bugs/1499675 Title: lightdm doesn´t ask for password Status in lightdm package in Ubuntu: Incomplete Bug description: For a long time (from previous versions) on my system I had only one user - Mark - with admin privileges, a password set and auto-login at startup. At boot I went directly to the Mark desktop. Now I add another user for my daughter - Carol - normal user but with no password. I switch off auto-login for both users. At startup I see the lightdm screen with users Carol and Mark, I can access Carol correctly by pressing "Log In" but when I choose Mark I am not asked for the password, I see the "Log In" button and enter directly in the Mark desktop without being asked for a password. I can also access Mark directly from the Carol account using the drop- down in the top left, again without being asked for a password. When I look in "user accounts" I see Carol with "no password" and Mark with a password set, neither have autologin set. I have looked at all the lightdm config files and can´t see anything obvious. I need to protect the Mark account from my growing children. I´d appreciate your help. Regards, Mark Rennie ProblemType: Bug DistroRelease: Ubuntu 14.04 Package: lightdm 1.10.5-0ubuntu1.1 ProcVersionSignature: Ubuntu 3.13.0-63.103-generic 3.13.11-ckt25 Uname: Linux 3.13.0-63-generic i686 ApportVersion: 2.14.1-0ubuntu3.15 Architecture: i386 CurrentDesktop: Unity Date: Fri Sep 25 12:03:47 2015 InstallationDate: Installed on 2011-07-18 (1529 days ago) InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release i386 (20110427.1) LightdmConfig: [SeatDefaults] greeter-session=unity-greeter user-session=ubuntu allow-guest=false SourcePackage: lightdm UpgradeStatus: Upgraded to trusty on 2014-08-14 (407 days ago) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/1499675/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp