diff --git a/macosx/Controller.m b/macosx/Controller.m
index 860e0c53d..0878602eb 100644
--- a/macosx/Controller.m
+++ b/macosx/Controller.m
@@ -296,7 +296,8 @@ static void sleepCallback(void * controller, io_service_t y, natural_t messageTy
             tr_bencDictAddStr(&settings, TR_PREFS_KEY_BIND_ADDRESS_IPV6, [[fDefaults stringForKey: @"BindAddressIPv6"] UTF8String]);
         
         tr_bencDictAddBool(&settings, TR_PREFS_KEY_BLOCKLIST_ENABLED, [fDefaults boolForKey: @"BlocklistNew"]);
-        tr_bencDictAddBool(&settings, TR_PREFS_KEY_BLOCKLIST_URL, [[fDefaults stringForKey: @"BlocklistURL"] UTF8String]);
+        if ([fDefaults objectForKey: @"BlocklistURL"])
+            tr_bencDictAddStr(&settings, TR_PREFS_KEY_BLOCKLIST_URL, [[fDefaults stringForKey: @"BlocklistURL"] UTF8String]);
         tr_bencDictAddBool(&settings, TR_PREFS_KEY_DHT_ENABLED, [fDefaults boolForKey: @"DHTGlobal"]);
         tr_bencDictAddStr(&settings, TR_PREFS_KEY_DOWNLOAD_DIR, [[[fDefaults stringForKey: @"DownloadFolder"]
                                                                     stringByExpandingTildeInPath] UTF8String]);