diff --git a/libs/ardour/luaproc.cc b/libs/ardour/luaproc.cc
index 9ac2b06c65..5c6df71999 100644
--- a/libs/ardour/luaproc.cc
+++ b/libs/ardour/luaproc.cc
@@ -520,7 +520,7 @@ LuaProc::configure_io (ChanCount in, ChanCount out)
 		try {
 			lua_dsp_configure (&in, &out);
 		} catch (luabridge::LuaException const& e) {
-			;
+			return false;
 		}
 	}