diff -Naur cyrus-imapd-2.4.10.orig/imap/userdeny_db.c cyrus-imapd-2.4.10/imap/userdeny_db.c
--- cyrus-imapd-2.4.10.orig/imap/userdeny_db.c	2011-07-04 17:05:01.000000000 +0200
+++ cyrus-imapd-2.4.10/imap/userdeny_db.c	2011-08-04 08:23:46.000000000 +0200
@@ -52,6 +52,8 @@
 #include <string.h>
 #include <errno.h>
 #include <syslog.h>
+#include <sys/types.h>
+#include <sys/stat.h>
 
 #include "cyrusdb.h"
 #include "global.h"
@@ -81,7 +83,9 @@
     if (!deny_dbopen) return 0;
 
     /* fetch entry for user */
+/*
     syslog(LOG_DEBUG, "fetching user_deny.db entry for '%s'", user);
+*/
     do {
 	r = DENYDB->fetch(denydb, user, strlen(user), &data, &datalen, NULL);
     } while (r == CYRUSDB_AGAIN);
@@ -175,6 +179,7 @@
 {
     int ret;
     char *tofree = NULL;
+    struct stat sbuf;
 
     if (!fname)
 	fname = config_getstring(IMAPOPT_USERDENY_DB_PATH);
@@ -185,7 +190,11 @@
 	fname = tofree;
     }
 
-    ret = (DENYDB->open)(fname, 0, &denydb);
+    if (stat(fname, &sbuf) == -1 && errno == ENOENT) {
+      ret = CYRUSDB_IOERROR;
+    } else {
+      ret = (DENYDB->open)(fname, 0, &denydb);
+    }
     if (ret == CYRUSDB_OK) {
 	deny_dbopen = 1;
     } else if (errno != ENOENT) {