diff --git a/src/mail.c b/src/mail.c
index 9c09fdc47..06ce1b266 100644
--- a/src/mail.c
+++ b/src/mail.c
@@ -1,4 +1,4 @@
-/* NetHack 3.6	mail.c	$NHDT-Date: 1451955080 2016/01/05 00:51:20 $  $NHDT-Branch: NetHack-3.6.0 $:$NHDT-Revision: 1.25 $ */
+/* NetHack 3.6	mail.c	$NHDT-Date: 1464222344 2016/05/26 00:25:44 $  $NHDT-Branch: NetHack-3.6.0 $:$NHDT-Revision: 1.27 $ */
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -84,7 +84,7 @@ void
 free_maildata()
 {
     if (mailbox)
-        free(mailbox);
+        free((genericptr_t) mailbox), mailbox = (char *) 0;
 }
 
 void