diff --git a/lib/adminlib.php b/lib/adminlib.php
index cc628317882..4f94c005a39 100644
--- a/lib/adminlib.php
+++ b/lib/adminlib.php
@@ -2579,7 +2579,8 @@ class admin_setting_special_debugdisplay extends admin_setting_configcheckbox {
         $name = 'debugdisplay';
         $visiblename = get_string('debugdisplay', 'admin');
         $description = get_string('configdebugdisplay', 'admin');
-        parent::admin_setting_configcheckbox($name, $visiblename, $description, '');
+        $default = ini_get('display_errors');
+        parent::admin_setting_configcheckbox($name, $visiblename, $description, $default);
     }
 
     function write_setting($data) {
@@ -2594,7 +2595,7 @@ class admin_setting_special_debugdisplay extends admin_setting_configcheckbox {
     function output_html() {
 
         if ($this->get_setting() === NULL) {
-            $currentsetting = ini_get('display_error');
+            $currentsetting = $this->defaultsetting;
         } else {
             $currentsetting = $this->get_setting();
         }
diff --git a/lib/setup.php b/lib/setup.php
index 28b0020ad52..e4e36dcd478 100644
--- a/lib/setup.php
+++ b/lib/setup.php
@@ -258,7 +258,9 @@ global $HTTPSPAGEREQUIRED;
 
 
 /// If we want to display Moodle errors, then try and set PHP errors to match
-    if (empty($CFG->debugdisplay)) {
+    if (!isset($CFG->debugdisplay)) {
+        //keep it as is during installation
+    } else if (empty($CFG->debugdisplay)) {
         @ini_set('display_errors', '0');
         @ini_set('log_errors', '1');
     } else {