After installing an update, my system no longer boots. I have full disk encryption (the one the installer sets up for you) enabled so it usually asks for the key only seconds after booting past GRUB. Now, it skips asking for the key, tries to load Gnome, and then goes to the screen pictured below. The system is a 64-bit System76 box running Ubuntu Gnome 13.04. This has happened to me once in the past however, on a Dell XPS 8300 64-bit running Ubuntu Gnome Remix 12.10. In that case I reinstalled the OS. However I want to actually fix the problem this time so I know how to handle it in the future. Also, it is extremely inconvenient to reinstall from scratch.
My suspicion is that something got screwed up in a config file in /boot such that it doesn't realize the disk is encrypted, but I didn't see anything when poking around in there. Do you have any ideas of how to fix it (besides re-installing the OS)??