diff --git a/libs/ardour/ardour/plugin_manager.h b/libs/ardour/ardour/plugin_manager.h
index 55879eea97..8b1fd3fbc6 100644
--- a/libs/ardour/ardour/plugin_manager.h
+++ b/libs/ardour/ardour/plugin_manager.h
@@ -159,12 +159,17 @@ public:
 	};
 	std::vector<std::string> get_all_tags (enum TagFilter) const;
 
-	/** plugins were added to or removed from one of the PluginInfoLists */
+	/** plugins were added to or removed from one of the PluginInfoLists
+	 * This implies PluginScanLogChanged.
+	 */
 	PBD::Signal0<void> PluginListChanged;
 
 	/** Plugin Statistics (use-count, recently-used) changed */
 	PBD::Signal0<void> PluginStatsChanged;
 
+	/** Plugin ScanLog changed */
+	PBD::Signal0<void> PluginScanLogChanged;
+
 	/** A single plugin's Hidden/Favorite status changed */
 	PBD::Signal3<void, ARDOUR::PluginType, std::string, PluginStatusType> PluginStatusChanged; //PluginType t, string id, string tag
 
diff --git a/libs/ardour/plugin_manager.cc b/libs/ardour/plugin_manager.cc
index 4321e0cc1d..f59d27eb06 100644
--- a/libs/ardour/plugin_manager.cc
+++ b/libs/ardour/plugin_manager.cc
@@ -3235,6 +3235,8 @@ PluginManager::rescan_plugin (ARDOUR::PluginType type, std::string const& path_u
 		save_scanlog ();
 		if (erased) {
 			PluginListChanged (); /* EMIT SIGNAL */
+		} else {
+			PluginScanLogChanged (); /* EMIT SIGNAL */
 		}
 		PluginScanMessage(X_("closeme"), "", false);
 		return false;
@@ -3275,6 +3277,7 @@ PluginManager::rescan_faulty ()
 		detect_ambiguities ();
 	} else {
 		save_scanlog ();
+		PluginScanLogChanged ();/* EMIT SIGNAL */
 	}
 }
 
@@ -3290,6 +3293,7 @@ PluginManager::scan_log (std::vector<boost::shared_ptr<PluginScanLogEntry> >& l)
 void
 PluginManager::clear_stale_log ()
 {
+	bool erased = false;
 	for (PluginScanLog::const_iterator i = _plugin_scan_log.begin(); i != _plugin_scan_log.end();) {
 		if (!(*i)->recent()) {
 			whitelist ((*i)->type (), (*i)->path (), true);
@@ -3299,11 +3303,15 @@ PluginManager::clear_stale_log ()
 				::g_unlink (fn.c_str ());
 			}
 			i = _plugin_scan_log.erase (i);
+			erased = true;
 		} else {
 			++i;
 		}
 	}
-	save_scanlog ();
+	if (erased) {
+		save_scanlog ();
+		PluginScanLogChanged ();/* EMIT SIGNAL */
+	}
 }
 
 void