I am having a problem similar to that asked (and solved) here: Can't enable GNOME Shell extensions. I have performed both of the "tweaks" explained in that solution (i.e., here and here); but that does not seem to help. My gnome-shell is version 3.2.1. When I run gnome-tweak-tool from a shell, I get the following output: CRITICAL: Unknown extension error CRITICAL: Unknown extension error CRITICAL: Unknown extension error CRITICAL: Unknown extension error CRITICAL: Unknown extension error CRITICAL: Unknown extension error CRITICAL: Unknown extension error (gnome-tweak-tool:7823): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width = 0' failed (gnome-tweak-tool:7823): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width = 0' failed (gnome-tweak-tool:7823): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width = 0' failed (gnome-tweak-tool:7823): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width = 0' failed (gnome-tweak-tool:7823): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width = 0' failed (gnome-tweak-tool:7823): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width = 0' failed (gnome-tweak-tool:7823): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width = 0' failed (gnome-tweak-tool:7823): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width = 0' failed (gnome-tweak-tool:7823): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width = 0' failed (gnome-tweak-tool:7823): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width = 0' failed (gnome-tweak-tool:7823): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width = 0' failed (gnome-tweak-tool:7823): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width = 0' failed (gnome-tweak-tool:7823): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width = 0' failed (gnome-tweak-tool:7823): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width = 0' failed (gnome-tweak-tool:7823): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width = 0' failed Has anyone actually solved this besides to the references above? I have made the suggested modifications from those sites.