Courier makes it simple to move your messages, account information and other settings from one computer to another. Your Courier mailbox file ( - with a .box file extension - contains everything you need to access your mail on any computer that has Courier installed; your messages, address book and account information and settings are all contained in this single file.

Simply copy the file to another computer, where you can open your mailbox in Courier by double-clicking on the mailbox file (or on a shortcut to the mailbox file), or by starting Courier from the Start menu and browsing for the desired mailbox.