ok, to get a list of users,
1- create new query
2- Type is Logging
3-Result Type "Roles and Permissions"
4- Label = "Principal"
this will get you a list of users, you can also have all the roles and permissions list for each user.
Hope this helps
TTP- create an automated task to email or create an issue to list all failed logins, good to know if someone is trying to break into your ePO.