Using local mailboxes with Thunderbirdand IMAP

Thunderbird—the free electronic mail program that LSCR recommends as a replacement for Eudora (which is no longer being developed)—allows you to retrieve and organize your messages using IMAP, the Internet Message Access Protocol. IMAP has a number of advantages over POP (Post Office Protocol), which is the way most users retrieve messages using Eudora. (This article is intended primarily for users migrating from Eudora with POP to Thunderbird with IMAP. Some campus Eudora users have already been using IMAP.)

What is IMAP?

IMAP is a way to access email messages and mailboxes that are stored on a mail server such as CalMail. Unlike POP, which allows only a single mailbox on the mail server, IMAP allows you to have multiple mailboxes (or "folders") on the server. For Eudora users using POP, all mailboxes were "local mailboxes"; that is, the mailboxes resided only on the computer that ran Eudora. As a result, people who checked their email from multiple locations (such from a computer on campus and another computer at home) were unable to access the same mailboxes from different computers; generally, only recent messages in the "In" mailbox were accessible.

Local and server folders

When you use Thunderbird with IMAP, there are two types of folders: server folders and local folders. Some people keep all their mail in server folders; however, the amount of space available on the server is limited, so users who keep all their mail on the server may periodically need to delete messages that are no longer necessary. (The limit on the amount of mail that can be kept on the server is called a "quota.") In some cases, users may want to save messages on their local computers—it's possible to do this with local folders. Local folders are useful for messages that you wish to keep, but do not need to access from multiple locations. You can easily copy or move messages from server folders to local volders, or vice versa.

Working with local folders

By default, there are two local folders created with ThunderBird: Unsent and Trash. These folders contain drafts of messages prior to being sent, and local messages that have been discarded, respectively. If you have imported mailboxes from Eudora, these will appear along with the other local folders. You can create as many local folders as you need. To create a new local folder, click on Local Folders in the pane on the left of the window, click on File menu in the upper left corner of the screen, then click New, then Folder.... You can also create folders within folders if you wish. (The procedure for creating server folders is essentially the same except you would would click on your server account in the left pane of the window. You can also change where you wish the new folder to reside in the the New Folder window.)

You can also right-click on Local Folders or the server account in the folder pane to create a new folder.

You can easily move or copy messages to local folders by choosing Move or Copy from the Message menu. You can also drag message headings to folders in the left pane. To copy instead of move messages, hold down the Control key (Windows) or Command key (Mac) while dragging the message headings. (The Command key on a Mac has a hollow Apple and a four-leaf-clover-like symbol on it.)