diff --git a/src/graphblas/reference/init.cpp b/src/graphblas/reference/init.cpp
index 5b0ffdf6e..d9a0e8d60 100644
--- a/src/graphblas/reference/init.cpp
+++ b/src/graphblas/reference/init.cpp
@@ -62,6 +62,7 @@ grb::RC grb::init< grb::reference >(
 	// set memory policy
 	numa_set_localalloc();
 #endif
+	grb::internal::reference_mapper.clear();
 	// done
 	return grb::SUCCESS;
 }