diff --git a/message/lib.php b/message/lib.php
index 72685cc109f..7d94aa6232f 100644
--- a/message/lib.php
+++ b/message/lib.php
@@ -1944,8 +1944,10 @@ function message_post_message($userfrom, $userto, $message, $format) {
     $eventdata->subject          = get_string_manager()->get_string('unreadnewmessage', 'message', fullname($userfrom), $userto->lang);
 
     if ($format == FORMAT_HTML) {
-        $eventdata->fullmessage      = '';
         $eventdata->fullmessagehtml  = $message;
+        //some message processors may revert to sending plain text even if html is supplied
+        //so we keep both plain and html versions if we're intending to send html
+        $eventdata->fullmessage = html_to_text($eventdata->fullmessagehtml);
     } else {
         $eventdata->fullmessage      = $message;
         $eventdata->fullmessagehtml  = '';