diff --git a/onyx/include/common/Exercice.class.php b/onyx/include/common/Exercice.class.php
index 99a1774f..ba648405 100644
--- a/onyx/include/common/Exercice.class.php
+++ b/onyx/include/common/Exercice.class.php
@@ -93,6 +93,9 @@ class Exercice
 
   function is_unlocked($team)
   {
+      if ($this->require == "")
+          return 1;
+
       $db = new BDD();
 
       $res = $db->unique_query("SELECT `id` FROM solved