After update my system to 15.04, I have an error message at the boot: 'starting build 219'.
The bug is known, its recommend to go to console mode and enter this command:
sudo systemctl enable sddm.service -f
But when I enter this command I get an error message:
Error getting authority: Error initializing authority: Could not connect: No such file or directory (g-io-error-quark, 1)
I had some similar errors with my system, and I found that it was an error with some fstab entries (external drives that were no longer physically connected). I just commented them out and the system booted as usual. Or you can try to reattach missing external devices.
You may get such an error if your display manager is not sddm.
Running the following can show which display manager you are using :
cat /etc/X11/default-display-manager
For example, if your display manager is /usr/sbin/gdm, running the following may help :
sudo systemctl enable gdm.service -f
