When you remove a user from a project, all items such as tasks and tracker artifacts that were assigned to the user are re-assigned to None.
If your project is a subproject of any other project, your project may have inherited some users from the parent project. To remove an inherited user, you must go to the parent project where that user is a direct member.
  1. Click PROJECT ADMIN from the Project Home menu.

  2. On the Project Admin Menu, click User Membership.

  3. From the list of current project members, select the user you want to remove and click Remove.