diff --git a/libs/ardour/region_factory.cc b/libs/ardour/region_factory.cc
index 5e408b2786..f739483821 100644
--- a/libs/ardour/region_factory.cc
+++ b/libs/ardour/region_factory.cc
@@ -620,10 +620,17 @@ RegionFactory::remove_regions_using_source (boost::shared_ptr<Source> src)
 {
 	Glib::Mutex::Lock lm (region_map_lock);
 
-	for (RegionMap::iterator i = region_map.begin(); i != region_map.end(); ++i) {
+	RegionMap::iterator i = region_map.begin();
+	while (i != region_map.end()) {
+
+		RegionMap::iterator j = i;
+		++j;
+		
 		if (i->second->uses_source (src)) {
 			region_map.erase (i);
                 }
+
+		i = j;
 	}
 }