The default Location of BOX file can be simply viewed at : C:\Program Files\IBM\Notes\Data
Mail.box is a sort of database which is instinctively created on the Domino server while activating Lotus Notes first time. It behaves as a temporary repository in which incoming/outgoing mails; applications are kept for a while. Notes Server creates various Mail.box database according to the number mentioned in the Configuration Settings Document. When the user works in Offline mode, Lotus Notes generate mail.box in which all sent messages are stored temporarily, till the time user does not link with Domino system. IBM Notes offer numerous locations to the users to work. When the user sets the Notes Location Offline, then Lotus Notes form Mail.box spontaneously in the Data Directory folder.
User.id file contains the following information to identify the authorized user of stored data in Lotus Notes and Domino Server environment.