Per http://moodle.org/mod/forum/discuss.php?d=76855#p45328sammarshallou6, I checked and noticed that $CFG->fullnamedisplay is not properly implemented for sorting on the /admin/user.php page. Currently, it checks to see if the sorting is by name and if so defaults to firstname; however, if the fullnamedisplay begins with lastname it makes sense to expect that it should sort by lastname. To accomplish this, I moved up the code that checks for fullnamedisplay to before the execution of the query to get the users. That way the $sort variable is properly set prior to executing the query. Peace - Anthony