Is an import process required?

A key question is whether you need to manually import anything at all. Please note the following:

• If you are migrating from Thunderbird, then all of your mail and application settings should transfer over seamlessly when you install Postbox. We highly recommend this migration path over a manual migration.
• If your account is using IMAP, then you do not need to import your messages since Postbox will download your folders and messages from your email server.
• If your account is using POP or POP3, then Postbox can download messages from your Inbox. Messages in other folders will need to be manually imported.
• Any messages stored on your local machine will need to be manually imported.

Manually migrate email from Thunderbird to Postbox

Again, we highly recommend that you migrate Thunderbird during the Postbox install process, but if you must do this manually, then read on!

1. Quit Postbox if it is currently running.
2. Within Thunderbird, compact your folders by selecting Compact Folders from the File menu. If your mailboxes are quite large, this could take several minutes. When compaction is complete, Quit Thunderbird.
3. As a precaution, backup Thunderbird by making a copy of your profile directory. Information on how to do this can be found within this article. Be sure to make a backup of your Postbox profile as well.
4. Find the mail folders you would like to copy from Thunderbird. On the Mac, they are located at: [your home folder]/Library/Thunderbird/Profiles/[your profile]/. On Windows, they are located at: C:\Documents and Settings\[Windows user name]\Application Data\Thunderbird\Profiles\[your profile].
5. Mail is contained in the following folders: Mail (for POP mail and Local Folders) and ImapMail (for IMAP mail).
6. Copy the contents of your Thunderbird ImapMail folder to your Postbox ImapMail folder located on the Mac at: [your home folder]/Library/Application Support/Postbox/Profiles/[your profile]/ and on Windows at: C:\Documents and Settings\[Windows user name]\Application Data\Postbox\Profiles\[Profile name]. Repeat this process for Mail/Local Folders, and Mail.
7. Start Postbox and you should be set to go!

For more migration options, please see this article.