What version of lightdm-gtk-greeter are you using? We did fix a leak in it a longer while ago, but it could practically be anything in your session that's leaking.
So what applications do you have running and what does htop say? -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1320989 Title: black screen after longer screen lock To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/light-locker/+bug/1320989/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs