diff --git a/gtk2_ardour/region_view.cc b/gtk2_ardour/region_view.cc
index 3312fc3929..a01ec941be 100644
--- a/gtk2_ardour/region_view.cc
+++ b/gtk2_ardour/region_view.cc
@@ -808,6 +808,9 @@ RegionView::update_coverage_frames (LayerDisplay d)
 		}
 
 		t = pl->find_next_region_boundary (t, 1);
+		if (t < 0) {
+			break;
+		}
 		me = new_me;
 	}