How do I query for work item not owned by members in Team Area?

Hi Natthapol, since workitem categories are associated with TeamAreas, you can use only the "FileAgainst is" in the query and adding another condition for TeamArea may not be necessary. Secondly, I don't see a way other than listing all the users individually in the Owned by condition.

If I understand the question correctly, something like the below screenshot should work.

I guess my question is how to make a list of users that's not a member of my Team Area to be used in Owned By.

Probably I was not very clear. If you notice the screen shot I did mentioned Owned by "is not" and you have to select all the users in the list who are not part of the TeamArea. So while creating the query you can select all users in the search box and deselect the ones who are members of the TeamArea.
I would probably agree if you say this is not a good way to achieve this but I am not aware of any other tricks.