diff --git a/htdocs/core/class/hookmanager.class.php b/htdocs/core/class/hookmanager.class.php
index ff6d364b8fe..cef41497381 100644
--- a/htdocs/core/class/hookmanager.class.php
+++ b/htdocs/core/class/hookmanager.class.php
@@ -131,7 +131,9 @@ class HookManager
 			dol_syslog(get_class($this)."::initHooks Loading hooks: ".join(', ', $arraytolog), LOG_DEBUG);
 		}
 
-		ksort($this->hooks[$context], SORT_NATURAL);
+		if (!empty($this->hooks[$context])) {
+			ksort($this->hooks[$context], SORT_NATURAL);
+		}
 
 		return 1;
 	}