You can find informations on how to get a stracktrace on https://wiki.ubuntu.com/Backtrace (see http://wiki.ubuntu.com/DebuggingProgramCrash if you need to enable a debug source), use the instruction to get infos on running softwares
** Changed in: gnome-settings-daemon (Ubuntu) Status: Invalid => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/743761 Title: Gnome reverts partially to default theme and fonts; "gnome- session[...]: GLib-GObject-CRITICAL: g_object_unref: assertion `G_IS_OBJECT (object)' failed" in syslog -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs