Hey all, Following this Railscast (http://railscasts.com/episodes/17-habtm- checkboxes) I have a set up a form with checkboxes that work great for updating records in a hatbm relationship. But it only works if I''m doing an update to an existing record. When I try to create, I get a validation error. In my app I have Sessions which can have many Learners. In the Session edit/create form there''s a list of all the Learners with check boxes for selecting them. I can edit a Session and check/uncheck Learners and the changes are saved. When I create a new session, I get a "Learners is invalid" validation error. This is probably happening because the Learner ids can''t be saved into the Learners_Sessions table without a session id, and the the session id isn''t created until save. So when I do this: def create @session = @user.project.sessions.new(params[:session]) if @session.save .... it throws out the validation error. Any ideas on how I can work around this? I could create a bare-bones Session object, save it and then update it with the full params, but that seems inelegant. I figure there has to be a better solution, I just don''t know what it is. Thanks, Ian