diff --git a/classes/module/ModuleGraph.php b/classes/module/ModuleGraph.php
index f8937fcd2..5790a92e5 100644
--- a/classes/module/ModuleGraph.php
+++ b/classes/module/ModuleGraph.php
@@ -222,7 +222,8 @@ abstract class ModuleGraphCore extends Module
 
 	protected function _displayCsv()
 	{
-		ob_end_clean();
+		if (ob_get_length())
+			ob_end_clean();
 		header('Content-Type: application/octet-stream');
 		header('Content-Disposition: attachment; filename="'.$this->displayName.' - '.time().'.csv"');
 		echo $this->_csv;