--- sh.c
+++ sh.c	2009-08-14 10:27:58.129901841 +0200
@@ -2153,6 +2153,7 @@ mailchk(void)
 
 	    while (readdir(mailbox))
 		mailcount++;
+	    closedir(mailbox);
 
 	    if (mailcount == 0)
 		continue;