diff --git a/install/install.php b/install/install.php
index d3b854c20ab3b25ea84ddad9ea55254767bfdf2b..02912d6394086885fff547431ae9d7c6281a3c53 100644
--- a/install/install.php
+++ b/install/install.php
@@ -81,6 +81,10 @@ if(!is_writable(dirname(ISPC_LOG_FILE))){
     die("ERROR: Cannot write to the directory ".dirname(ISPC_LOG_FILE).". Are you root or sudo ?\n\n");
 }
 
+if(is_dir('/root/ispconfig') || is_dir('/home/admispconfig')) {
+	die('This software can not be installed on a server wich runs ISPConfig 2.x.');
+}
+
 //** Select the language
 $conf['language'] = $inst->simple_query('Select language', array('en','de'), 'en');
 
diff --git a/install/update.php b/install/update.php
index 8f25e42cce0bc794f2e757a5a4742f2e6f7cf4a1..8d1022a79e4a3260a5e7bee8ebec1a167e331ad7 100644
--- a/install/update.php
+++ b/install/update.php
@@ -53,6 +53,11 @@ require_once('lib/installer_base.lib.php');
 //** Installer/updater logfile
 define('ISPC_LOG_FILE', '/var/log/ispconfig_install.log');
 
+//** Check for ISPConfig 2.x versions
+if(is_dir('/root/ispconfig') || is_dir('/home/admispconfig')) {
+	die('This software can not be installed on a server wich runs ISPConfig 2.x.');
+}
+
 //** Get distribution identifier
 $distname = get_distname();