I recently left my machine (running Xubuntu 12.04) up while it upgraded some 300 different things. I have a Hybrid Graphics NVIDIA Optimus system, and it was working perfectly with Bumblebee 3.0 up until the upgrade. Since the upgrade, fonts don't render correctly (certain pixels in white letters turn black) and Bumblebee throws
[430.015513] [ERROR]The Bumblebee daemon has not been started yet or the socket path /var/run/bumblebee.socket was incorrect.
[430.015627] [ERROR]Could not connect to bumblebee daemon - is it running?
when I try to run anything with the NVIDIA chip.
I googled the errors and a reboot seems to have fixed it for most. I've rebooted, re-installed bumblebee, and updated my nvidia drivers, all to no avail.