Index: libs/ardour/region_factory.cc
===================================================================
--- libs/ardour/region_factory.cc	(revision 11846)
+++ libs/ardour/region_factory.cc	(working copy)
@@ -619,10 +619,13 @@
 RegionFactory::remove_regions_using_source (boost::shared_ptr<Source> src)
 {
 	Glib::Mutex::Lock lm (region_map_lock);
+	RegionMap::iterator	save;
 
 	for (RegionMap::iterator i = region_map.begin(); i != region_map.end(); ++i) {
+	  save = region_map.upper_bound(i->first);
 		if (i->second->uses_source (src)) {
 			region_map.erase (i);
+			i = save;
                 }
 	}
 }