--- libmalloc/libmalloc-521.120.7/tests/malloc_zone_unregister_test.c
+++ libmalloc/libmalloc-474.0.13/tests/malloc_zone_unregister_test.c
@@ -18,7 +18,6 @@
 
 T_DECL(malloc_zone_unregister_establish_custom_default_zone,
 		"Unregister all initial zones and register a custom default zone",
-		T_META_ENVVAR("MallocProbGuard=0"),
 		T_META_ENVVAR("MallocNanoZone=1"))
 {
   void *ptr = malloc(7);