Ubuntu – Ubuntu 14.04 + Gnome 3.10 = cannot open settings

I've encountered a problem. After some time of using my ubuntu 14.04 + gnome shell i happend not to be able to open system settings. When I open it usually just nothing happens or system error occurs and it asks me to send a report.I've tried to run it from command line, but here's what i get:

marcin@marcin-laptop:~$ sudo gnome-control-center

(gnome-control-center.real:3201): GLib-GObject-WARNING **: cannot derive 'GnomeControlCenter' from non-fundamental parent type 'CcShell'

(gnome-control-center.real:3201): GLib-CRITICAL **: g_once_init_leave: assertion 'result != 0' failed

(gnome-control-center.real:3201): GLib-GObject-CRITICAL **: g_object_new: assertion 'G_TYPE_IS_OBJECT (object_type)' failed

I've found in google that

Downgrading the library 1:3.10.1-0ubuntu1~saucy3 to 1:3.6.3-0ubuntu45 fixed the issue for me too.

(source: https://bugs.launchpad.net/ubuntu-gnome/+bug/1309419/comments/10)

might help but i don't know how to do it (I'm still new to Linux system).
I would really appreciate if you could help 🙂