diff --git a/src/mzscheme/src/stxobj.c b/src/mzscheme/src/stxobj.c
index f6d235ef06..087fd8b2af 100644
--- a/src/mzscheme/src/stxobj.c
+++ b/src/mzscheme/src/stxobj.c
@@ -5321,7 +5321,7 @@ Scheme_Object *scheme_stx_source_module(Scheme_Object *stx, int resolve, int sou
   /* Inspect the wraps to look for a self-modidx shift: */
   WRAP_POS w;
   Scheme_Object *srcmod = scheme_false, *chain_from = NULL, *er;
-  Scheme_Hash_Table *export_registry;
+  Scheme_Hash_Table *export_registry = NULL;
 
   WRAP_POS_INIT(w, ((Scheme_Stx *)stx)->wraps);