Why is plymouthd crashing on startup?
I have experienced the same error when I first installed Ubuntu 13.10 on the toshiba harman/kardon this week.
I solved the error with a single command:
Open a Terminal (Ctrl+Alt+T) and type:
sudo chown -R $USER: /lib/plymouth
Then all the permission issues are solved and the error is gone in the next boot.
sudo apt-get install plymouth-x11
That did help me with the issue.
A possible solution not mentioned here is to run:
sudo dpkg-reconfigure Plymouth
From: https://bugs.launchpad.net/ubuntu/+source/ubuntu-gnome-default-settings/+bug/1536771