This is an intermittent issue that occurs more often than not when logging into my user session. The original install was F38-beta and I had the described issue then and it could be rectified in a terminal by issuing the command: mate-panel --replace & Now since upgrading to the F38 release I am still having this issue. I have in all cases been able to restore the panels with the noted terminal command. The Mate Version: 1.26.1 Reproducible: Sometimes Mate Desktop Errors culled from .xsession-errors mate-session[1091]: WARNING: Application 'mate-panel.desktop' failed to register before timeout (caja:1457): Gtk-WARNING **: 07:25:27.876: Failed to register client: GDBus.Error:org.gnome.SessionManager.AlreadyRegistered: Unable to register client (mate-power-manager:1481): PowerManager-WARNING **: 07:25:28.077: Failed to get session for pid 1481: The name is not activatable (mate-power-manager:1481): PowerManager-WARNING **: 07:25:28.090: could not map keysym 1008ffa8 to keycode ** Message: 07:25:28.425: Initializing gksu extension... ** (mate-settings-daemon:1354): CRITICAL **: 07:25:35.639: setup_background: assertion 'manager->bg == NULL' failed (mate-power-manager:1481): Gdk-CRITICAL **: 07:25:46.946: gdk_window_thaw_toplevel_updates: assertion 'window->update_and_descendants_freeze_count > 0' failed ** (mate-settings-daemon:1354): WARNING **: 08:23:11.373: failed to send session response: Connection was disconnected before a reply was received (mate-settings-daemon:1354): GLib-GObject-CRITICAL **: 08:23:11.393: g_object_unref: assertion 'G_IS_OBJECT (object)' failed
After deleting /home/<user>/.config and reconfiguring my settings I am no longer having the missing panel problem. Since it appears no others are having this problem I consider it closed and will mark it so in the status.