diff --git a/gtk2_ardour/ardour_ui_session.cc b/gtk2_ardour/ardour_ui_session.cc
index e92446a24c..612141004e 100644
--- a/gtk2_ardour/ardour_ui_session.cc
+++ b/gtk2_ardour/ardour_ui_session.cc
@@ -71,6 +71,7 @@
 #include "session_dialog.h"
 #include "session_archive_dialog.h"
 #include "timers.h"
+#include "ui_config.h"
 #include "utils.h"
 
 #ifdef WINDOWS_VST_SUPPORT
@@ -542,7 +543,9 @@ ARDOUR_UI::load_session_stage_two (const std::string& path, const std::string& s
 			psd.start ();
 		}
 		if (!u.empty()) {
-			show_plugin_manager ();
+			if (scan_now || UIConfiguration::instance().get_show_manager_if_plugins_are_missing ()) {
+				show_plugin_manager ();
+			}
 		}
 	}
 
diff --git a/gtk2_ardour/rc_option_editor.cc b/gtk2_ardour/rc_option_editor.cc
index 6f1ddc5276..597dd8683c 100644
--- a/gtk2_ardour/rc_option_editor.cc
+++ b/gtk2_ardour/rc_option_editor.cc
@@ -3828,6 +3828,16 @@ These settings will only take effect after %1 is restarted.\n\
 					    _("<b>When enabled</b> additional information for every plugin is shown to the Plugin Manager Log."));
 #endif
 
+	bo = new BoolOption (
+			"show-manager-if-plugins-are-missing",
+			_("Open Plugin Manager window when missing plugins are found"),
+			sigc::mem_fun (UIConfiguration::instance(), &UIConfiguration::get_show_manager_if_plugins_are_missing),
+			sigc::mem_fun (UIConfiguration::instance(), &UIConfiguration::set_show_manager_if_plugins_are_missing)
+			);
+	add_option (_("Plugins"), bo);
+	Gtkmm2ext::UI::instance()->set_tip (bo->tip_widget(),
+					    _("<b>When enabled</b> the Plugin Manager is display at session load if the session contains any plugins that are missing, or plugins have been updated and require a rescan."));
+
 	bo = new BoolOption (
 		"new-plugins-active",
 			_("Make new plugins active"),
diff --git a/gtk2_ardour/ui_config_vars.h b/gtk2_ardour/ui_config_vars.h
index 3bc25bf222..d29f2079b7 100644
--- a/gtk2_ardour/ui_config_vars.h
+++ b/gtk2_ardour/ui_config_vars.h
@@ -64,6 +64,7 @@ UI_CONFIG_VARIABLE (bool, update_editor_during_summary_drag, "update-editor-duri
 UI_CONFIG_VARIABLE (bool, never_display_periodic_midi, "never-display-periodic-midi", true)
 UI_CONFIG_VARIABLE (bool, sound_midi_notes, "sound-midi-notes", false)
 UI_CONFIG_VARIABLE (bool, show_plugin_scan_window, "show-plugin-scan-window", false)
+UI_CONFIG_VARIABLE (bool, show_manager_if_plugins_are_missing, "show-manager-if-plugins-are-missing", true)
 UI_CONFIG_VARIABLE (bool, show_zoom_tools, "show-zoom-tools", true)
 UI_CONFIG_VARIABLE (bool, use_mouse_position_as_zoom_focus_on_scroll, "use-mouse-position-as-zoom-focus-on-scroll", true)
 UI_CONFIG_VARIABLE (bool, use_time_rulers_to_zoom_with_vertical_drag, "use-time-rulers-to-zoom-with-vertical-drag", false)