Since last week usb devices and CDs don't mount automatically anymore. USB
devices show up in gnome-disks and can be mounted manually from this
application (see error-messages below). I never had to use gnome-disks before.
After some googling I also found "udisksctl mount /dev/sdc1" which also works
without error-messages.

Current versions:
kernel 3.16.7-29-desktop x86_64
gnome-version: /usr/bin/gnome-session 3.14.0

changes last week: added repo Graphics Project (openSUSE_13.2) because of new
scanner that would only work with sane-backends-1.0.25.

Errors when mounting the usb device from gnome-disks:
------------------snip--------------------
** (gnome-disks:11509): CRITICAL **: atk_object_ref_state_set: assertion
'ATK_IS_OBJECT (accessible)' failed

(gnome-disks:11509): Gtk-CRITICAL **: gtk_accessible_get_widget: assertion
'GTK_IS_ACCESSIBLE (accessible)' failed
------------------snap--------------------

I'd like to do some debug work by myself, but I'm not sure where to start. Thus
any help is appreciated.