diff --git a/main/inc/lib/main_api.lib.php b/main/inc/lib/main_api.lib.php
index 1007d0b221..088a6e129a 100644
--- a/main/inc/lib/main_api.lib.php
+++ b/main/inc/lib/main_api.lib.php
@@ -1012,6 +1012,11 @@ function api_get_user_courses($userid, $fetch_session = true) {
  */
 function _api_format_user($user, $add_password = false) {
     $result = array();
+
+    if (api_is_anonymous()) {
+        return $user;
+    }
+
     if (isset($user['firstname']) && isset($user['lastname'])) {
         $firstname = $user['firstname'];
         $lastname = $user['lastname'];
@@ -2117,7 +2122,7 @@ function api_is_platform_admin($allow_sessions_admins = false) {
         return true;
     }
     global $_user;
-    return $allow_sessions_admins && $_user['status'] == SESSIONADMIN;
+    return $allow_sessions_admins && isset($_user['status']) && $_user['status'] == SESSIONADMIN;
 }
 
 /**
@@ -2353,7 +2358,7 @@ function api_is_coach($session_id = 0, $course_code = null) {
  */
 function api_is_session_admin() {
     global $_user;
-    return $_user['status'] == SESSIONADMIN;
+    return isset($_user['status']) && $_user['status'] == SESSIONADMIN;
 }
 
 /**
@@ -2362,7 +2367,7 @@ function api_is_session_admin() {
  */
 function api_is_drh() {
     global $_user;
-    return $_user['status'] == DRH;
+    return isset($_user['status']) && $_user['status'] == DRH;
 }
 
 /**
@@ -2371,7 +2376,7 @@ function api_is_drh() {
  */
 function api_is_student() {
     global $_user;
-    return $_user['status'] == STUDENT;
+    return isset($_user['status']) && $_user['status'] == STUDENT;
 
 }
 /**
@@ -2380,7 +2385,7 @@ function api_is_student() {
  */
 function api_is_teacher() {
     global $_user;
-    return $_user['status'] == COURSEMANAGER;
+    return isset($_user['status']) && $_user['status'] == COURSEMANAGER;
 }
 
 /**
@@ -3486,9 +3491,12 @@ function api_get_visual_theme() {
 
         if (api_get_setting('user_selected_theme') == 'true') {
             $user_info = api_get_user_info();
-            $user_theme = $user_info['theme'];
-            if (!empty($user_theme)) {
-                $visual_theme = $user_theme;                // User's theme.
+            if (isset($user_info['theme'])) {
+                $user_theme = $user_info['theme'];
+
+                if (!empty($user_theme)) {
+                    $visual_theme = $user_theme;                // User's theme.
+                }
             }
         }