diff --git a/lib/Controller/CallController.php b/lib/Controller/CallController.php
index 59ce43c58a8..b80b9ccbd6a 100644
--- a/lib/Controller/CallController.php
+++ b/lib/Controller/CallController.php
@@ -188,7 +188,7 @@ public function downloadParticipantsForCall(string $format = 'csv'): DataDownloa
 		fseek($output, 0);
 
 		// Clean the room name
-		$cleanedRoomName = preg_replace('/[\/\\:*?"<>|\- ]+/', '-', $this->room->getName());
+		$cleanedRoomName = preg_replace('/[\/\\\\:*?"<>|\- ]+/', '-', $this->room->getName());
 		// Limit to a reasonable length
 		$cleanedRoomName = substr($cleanedRoomName, 0, 100);