Q. My volume indicator is broken after the upgrade to Xubuntu 13.10. The sound still works.
A. This is a known bug, but can be easily fixed:
In a terminal window, run:
sudo nano /usr/share/dbus-1/services/indicator-sound.service
Modify the line:
Exec=/usr/lib/x86_64-linux-gnu/indicator-sound/indicator-sound-service
to
Exec=/usr/lib/indicator-sound-gtk2/indicator-sound-service
Save (Ctrl+X -> press Y to save) and reboot.