Sounds like a dupe of lp #787821. X isn't crashing; something is listening to the enter key and forcing X to quit.
You should elaborate a bit more on your setup and steps to reproduce it. See if any of the details in the comments to bug 787821 match up with your experience. ** Package changed: xorg-server (Ubuntu) => plymouth (Ubuntu) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/801014 Title: Xorg crashed with SIGQUIT To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/plymouth/+bug/801014/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs