diff --git a/htdocs/core/class/fileupload.class.php b/htdocs/core/class/fileupload.class.php
index 4dcfb55f781..ff7dfc622b8 100644
--- a/htdocs/core/class/fileupload.class.php
+++ b/htdocs/core/class/fileupload.class.php
@@ -577,7 +577,10 @@ class FileUpload
 				}
 			}
 		}
+		// Return result in json format
 		header('Content-type: application/json');
 		echo json_encode($success);
+
+		return null;
 	}
 }