diff --git modules/system/system.mail.inc modules/system/system.mail.inc
index 14ba64f..adda562 100644
--- modules/system/system.mail.inc
+++ modules/system/system.mail.inc
@@ -67,7 +67,7 @@ class DefaultMailSystem implements MailSystemInterface {
     // but some MTAs incorrectly replace LF with CRLF. See #234403.
     $mail_headers = join("\n", $mimeheaders);
     if (isset($message['Return-Path']) && !ini_get('safe_mode')) {
-      $mail_result = mail(
+      $mail_result = @mail(
         $message['to'],
         $mail_subject,
         $mail_body,