How to list duplicate nodes based on title with views
The filter should be on content:nid. Set it to aggregate on COUNT, and 'Is greater than' value 1.

Then check all of your fields that you have added. None of the fields for nodes with the same title should output a different value. Title for instance, can be unique, depending on how you output it. If you for instance output it as a link (the default), then for each title that is the same, but that belongs to another node, the link is unique, therefore you view won't perform the way you want it to. So deselect 'Link this field to the original piece of content' and it should work.