In the user's profile, when editing the Messaging preferences, a click on the user's name in the bred crumb menu gives a 404 error.
There is an error in the URL. It states for example
Change has to me made in file /messages/edit.php at line 181
$navlinks = array('name' => $userfullname,
'link' => "$CFG->wwwroot/user/view.php?id=$user->id&course=$course->id",
'type' => 'misc');