Printer-friendly versionEven though Mozilla Thunderbird is a fantastic email client, there are people who (for one reason or another) need to switch back to Microsoft Outlook Express (OE) or Outlook. However, Thunderbird still doesn't have an "Export" feature which would export mail archives in a format understandable by OE or Outlook. IMAPSize can be of great help in this process and this page explains how to perform the migration.
Mozilla Thunderbird stores emails in the mbox format. Outlook Express stores email messages in propitiatory *.dbx files but understands *.eml, which are plain text files. MS Outlook stores messages in *.pst files which are binary propitiatory (Microsoft) files. Here are the steps you have to take:
1. Compact your Thunderbird folders (optional)
Thunderbird keeps messages in mbox files even after they have been deleted. If you don't want to include deleted messages in the conversion, you have to compact your folders in Thunderbird. Right click a folder and select "Compact This Folder". This will completely remove deleted messages from the folders mbox file.
2. Locate mbox files in Thunderbird
Thunderbird stores messages in the Profile Folder, in the Mail and (if you use IMAP) ImapMail folders. Each mail folder (Inbox, Sent, etc.) is stored as two files
