diff --git a/libs/ardour/panner_shell.cc b/libs/ardour/panner_shell.cc
index 75543433c5..064554eac6 100644
--- a/libs/ardour/panner_shell.cc
+++ b/libs/ardour/panner_shell.cc
@@ -119,8 +119,8 @@ PannerShell::configure_io (ChanCount in, ChanCount out)
 
 	PannerInfo* pi = PannerManager::instance().select_panner (in, out, _user_selected_panner_uri);
 	if (!pi) {
-		cerr << "No panner found: check that panners are being discovered correctly during startup.\n";
-		assert (pi);
+		fatal << _("No panner found: check that panners are being discovered correctly during startup.") << endmsg;
+		/*NOTREACHED*/
 	}
 
 	DEBUG_TRACE (DEBUG::Panning, string_compose (_("select panner: %1\n"), pi->descriptor.name.c_str()));