diff --git a/inc/lib_base.php b/inc/lib_base.php
index 506bca221089c8009cdf654e7144f3102418ed6f..3a8ad7163f86c0986d839e2da095e511718618b8 100755
--- a/inc/lib_base.php
+++ b/inc/lib_base.php
@@ -152,7 +152,7 @@ class OC_UTIL {
     global $CONFIG_BACKUPDIRECTORY;
     global $CONFIG_ENABLEBACKUP;
     $error='';
-    $f=@fopen($SERVERROOT.'/config/config.php','a+');
+    $f=@fopen($SERVERROOT.'/config/config.php','w+');
     if(!$f) $error.='Error: Config file (config/config.php) is not writable for the webserver.<br/>';
     @fclose($f);
     if(!is_callable('sqlite_open') and !is_callable('mysql_connect')){