I have this problem too.
Ubuntu 14.10 x86_64 Unity 7.3.1+14.10.20141016-0ubuntu1
Using a multi seat setup (2 users working the same time on different screens connected to different VGA cards).
BTW, I use "sudo loginctl unlock-sessions" as a workaround.
Very harmful bug and hurts a lot the Wife Acceptance Factor :-(
I have this problem too.
Ubuntu 14.10 x86_64 10.20141016- 0ubuntu1
Unity 7.3.1+14.
Using a multi seat setup (2 users working the same time on different screens connected to different VGA cards).
BTW, I use "sudo loginctl unlock-sessions" as a workaround.
Very harmful bug and hurts a lot the Wife Acceptance Factor :-(