Well, if this only happens on Linux Mint, you are on the wrong bug tracker. I added the Linux Mint task to the report.
With that said, the lightdm developers are possibly willing to add whatever is required to address this issue, but in that case they need to know - really know - what would be required. Myself is working with Ubuntu and sometimes the official flavors, so I can't help there. As regards your ideas in comment #5, the first one is already there in /usr/lib/lightdm/guest-session-auto.sh. When I had a quick look in Xubuntu, I got the impression that the xscreensaver settings are saved in ~/.xscreensaver rather than as gsettings values, but I may not have got the whole picture. So the ball is in your court again. ;) ** Also affects: linuxmint Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to lightdm in Ubuntu. https://bugs.launchpad.net/bugs/1610619 Title: Xscreen saver and lightdm prevent use of operating system (total lockout) after guest session screen lock Status in Linux Mint: New Status in xscreensaver: New Status in lightdm package in Ubuntu: Incomplete Bug description: Steps to reproduce bug: 1) Install xubuntu or mint xfce 2) download and set lightdm as desktop manager 3) sign in to a guest session and either close your laptop lid or allow timeout to start screen lock Why this is a bug: xscreensaver will not accept a blank/null password, and with a blank/null password assigned to the guest session, the xscreensaver client will not allow the user to continue their session or login as a new user (because you cannot login as a new user as xscreensaver does not support lightdm for this feature. Why this is severe: when xscreensaver locks the guest user out of their session, all other users are similarly locked out. Being so locked out, the computer most be hard-reset/rebooted and any documents and processes not saved prior to the guest session being logged in is lost. Why this is a lightdm bug: Because lightdm is not setting the gconf setting to disable the lock screen feature for guest sessions Why this is a xscreensaver bug: xscreensaver does not support any dm other than mdm To manage notifications about this bug go to: https://bugs.launchpad.net/linuxmint/+bug/1610619/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp