From MozillaZine Knowledge Base
Since Thunderbird and Mozilla Suite use the same file formats, it is not difficult to move your mail, address books, and other mail-related files from Thunderbird to Mozilla Suite. The procedure below assumes you have not yet been using the Mozilla Suite for mail; if you have, then follow the instructions in Combining two profiles to merge the two profiles.
- Back up your entire Mozilla Suite profile folder so that you can restore it later if something goes wrong.
- Set up your accounts in Mozilla Suite as you did in Thunderbird.
- Shut down Mozilla Suite.
- In Thunderbird, move all your mail to a temporary, local folder.
- Shut down Thunderbird.
- Copy the "Mail" and "News" directories/folders from your Thunderbird profile to the corresponding location in your Mozilla Suite profile.
- Start up Mozilla Suite and verify that your mail is in place.
You might want to copy these files also:
- address books
- "cookies.txt", "cookperm.txt" and "hostperm.1": cookies settings/whitelist
- "msgFilterRules.dat": message filters
- "popstate.dat": keeps track of which messages have been downloaded from the server (for POP3 mail accounts)
- " training.dat": junk-mail training data
Do not copy the "prefs.js" file.