When I try to start Rhythmbox its window remains only for few seconds then it disappears and I get "An internal Ubuntu error" message. Even if I try to open an MP3 file I see the same scenario.
Tried to reinstall it (twice :D)
Started from command line:
(rhythmbox:9164): Gtk-CRITICAL **: gtk_css_provider_load_from_path: assertion 'path != NULL' failed
(rhythmbox:9164): GLib-GObject-CRITICAL **: object SoupServer 0x2afc3e0 finalized while still in-construction
(rhythmbox:9164): GLib-GObject-CRITICAL **: Custom constructor for class SoupServer returned NULL (which is invalid). Please use GInitable instead.
Unable to open ~/.mtpz-data for reading, MTPZ disabled.Segmentation fault (core dumped)
UPDATE
Just found a bug report to launchpad: https://bugs.launchpad.net/ubuntu/+source/rhythmbox/+bug/1299245 , but the problem does not seem to be fixed