Index: user.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/user/user.module,v
retrieving revision 1.753
diff -u -F^f -r1.753 user.module
--- user.module	2 Feb 2007 15:25:25 -0000	1.753
+++ user.module	8 Feb 2007 22:04:42 -0000
@@ -585,7 +585,7 @@ function user_block($op = 'list', $delta
           // Perform database queries to gather online user lists.  We use s.timestamp
           // rather than u.access because it is much faster is much faster..
           $anonymous_count = sess_count($interval);
-          $authenticated_users = db_query('SELECT u.uid, u.name FROM {users} u INNER JOIN {sessions} s ON u.uid = s.uid WHERE s.timestamp >= %d AND s.uid > 0 ORDER BY s.timestamp DESC', $interval);
+          $authenticated_users = db_query('SELECT DISTINCT u.uid, u.name FROM {users} u INNER JOIN {sessions} s ON u.uid = s.uid WHERE s.timestamp >= %d AND s.uid > 0 ORDER BY s.timestamp DESC', $interval);
           $authenticated_count = db_num_rows($authenticated_users);
 
           // Format the output with proper grammar.