I also tried debugging via gnome-control-center --verbose and gnome- control-center. Same results, I doubt this will help solving the bug since the same GLib-GObject-CRITICAL error happens with all account adding operations.
ilari@NAFAC-HP:~$ gnome-control-center credentials-cc-panel-Message: cc-credentials-account-applications-model.vala:153: No valid plugin found for application 'unity-scope-gdocs' with account '1' credentials-cc-panel-Message: cc-credentials-account-applications-model.vala:153: No valid plugin found for application 'shotwell' with account '1' credentials-cc-panel-Message: cc-credentials-account-applications-model.vala:153: No valid plugin found for application 'unity-lens-photos' with account '1' (gnome-control-center:6380): GLib-GObject-CRITICAL **: g_value_unset: assertion `G_IS_VALUE (value)' failed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1131263 Title: Gwibber does not add Facebook account, external browser says "Success". To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gwibber/+bug/1131263/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs