diff --git a/src/vm.c b/src/vm.c
index b4639e43e..a271af28a 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -378,7 +378,6 @@ mrb_env_unshare(mrb_state *mrb, struct REnv *e, mrb_bool noraise)
     stack_copy(p, e->stack, len);
     e->stack = p;
     MRB_ENV_CLOSE(e);
-    mrb_write_barrier(mrb, (struct RBasic *)e);
     return TRUE;
   }
   else {