I recently set up Ubuntu 13.04 amd64 and checked the box for full disk encryption at the installation.
It worked fine, but yesterday Ubuntu ran an update and now with the new kernel (3.8.0-29-generic) my system doesn't boot any longer (with the old in it still works). It says the following:
"There appears to be one or more degraded LVM volumes, and your root device may depend on the LVM volumes being online. One or more of the following LVM volumes are degraded: Parse error at byte 611 (line 21): unexpected token Failed to load config file /etc/lvm/lvm.conf Gave up waiting for root device. Common problems: - Boot args (cat /proc/cmdline) - Check rootdelay= (did the system wait long enough?) - Check root= (did the system wait for the right device?) - Missing modules (cat /proc/modules; ls /dev) ALERT! /dev/mapper/ubuntu--vg-root does not exist. Dropping to a shell!"