On Access 2007, I have an existing database that was set up a long time ago. I want to add a Field to it. But when I right-click on the columns "Add Field" is missing. "Add existing field" is there but nor "Add Field". On the menus bar, "Datasheet" is missing - the last item on the Menu Bar is "Database Tools". And when I go along the fields to the end, there is no "Add New Field" column. I am guessing that somehow the database has locked the ability to add new fields but I cannot see how to unlock this. Thanks for any help with this.