How to migrate your Thunderbird mail to Outlook

by tuhlmann on August 15, 2006 Posted in Business,Programming

Now, Thunderbird is a wonderful email client. I like it. I really do! For instance there is that nifty little feature which let’s you edit a sent mail as if it were brand new. Cool.

But in a corporate environment where everybody else is exchanging contacts, appointments and other PIM data via Outlook it’s just uncool to open you vcard files with an ordinary editor. So I decided to jump upon the Outlook wagon.

But I didn’t want to loose my Thunderbird mail archive which keeps mails of my different projects as reference points. The problem however is that Outlook can’t directly import mail from Thunderbird, only from Eudora and Outlook Express. Outlook Express in turn can import from older versions of Netscape Communicator, but not from Thunderbird. But I wouldn’t write this entry if I didn’t succeed. So here’s what I did:

  • I installed Netscape Communicator 4.78 (here) and created an email account in Netscape Messenger. After that I closed the Messenger
  • Netscape put my user data into C:\Programme\Netscape\Users\tuhlmann. Within that directory there is a folder called ‘Mail’. Rename it and create a new folder ‘Mail’.
  • Copy the content of Thunderbirds ‘Local Folders’ directory into this ‘Mail’ dir. Thunderbird usually stores it’s profiles under C:\Dokumente und Einstellungen\\Anwendungsdaten\Thunderbird. Of course on an english windows the names would differ.
  • After copying the tree remove all the .msf files (in the new location, not on Thunderbird’s side)
  • Then start Netscape Messenger. You should now see all your mails and folders. Highlight all folders and choose File->Compress. This will create Netscapes old index. After that close Netscape again.
  • Then start Outlook Express and create a mail account there. Then say Import from Netscape Communicator and choose the ‘Mail’ directory of Netscape Messenger. The import should begin now. In the end all your mails should now be available from Outlook Express. Now you close Outlook Express
  • Last step: Start Outlook and create- yep, you guessed it- a mail account. No import your mail from Outlook Express. In the end, all your mail is available from Outlook (I used Outlook 2003 here but I guess it will work with older versions, too.).

You still have to recreate all filters. And I did not look into migrating the spam filter training data.

Maybe this is a product idea: Create a mail tool migrator which can migrate form/to different mail systems…

I hope this little howto will be useful for someone…

{ 13 comments… read them below or add one }

Vangoghnads February 28, 2007 at 11:22 pm

Perfect – exactly what I needed. Migrated over 5000 archived email folders using your method. Not a single hitch…

James June 8, 2007 at 11:20 pm

Thank you so much!

Zoltan July 12, 2007 at 6:47 pm

Works like a dream. Thanks a lot!

Peter French April 13, 2008 at 1:25 am


There is another method – create a new email account in Outlook that you don’t have in Thunderbirdands simply forward the Thunderbird mail.

I like Thunderbird but as I operate 3 distinct businesses it is really messy, for me anyway, to change identities – sometimes it works and sometimes it doesn’t, or does 3 messages later.

Ajoy September 26, 2008 at 6:44 am


Hey it is a fantastic article, thanks, u really did a great job.
Keep going.

Sharad December 16, 2008 at 9:23 am

what a wantastic idea, i got all my mails from thunderbird to outlook express with a little bit lang related problem…… could you please share with us that how can i import the same to microsoft outlook……………

Torsten December 16, 2008 at 9:39 am

Hi Sharad,

please see the last point in this article- it explains how you can import from Outlook Express into Outlook.

Stephen July 21, 2009 at 8:33 pm


Thank you for sharing your solution. This worked great. I was only unable to pull in my sent mail for some reason.

Sameer July 23, 2009 at 12:31 pm

Thanks a Million it works like Breeze

Ivan Ordonez September 10, 2009 at 11:49 pm

Thank you. It worked like a charm.

David Jones December 9, 2009 at 3:11 pm

Thank you!!!!!!!

Aristarkhos January 5, 2010 at 10:04 am

Hi Torsten,
Thanks for your workaround. I have also found a free tool that converts the Thunderbird files to eml. The Netscape step is replaced with the converter tool. The rest of the steps, I think, remain the same. That is, Tb – IMAPSize – OE – Outlook 2003

I moved from OE to Thunderbird because I had always wanted to migrate. I liked using the Add-ons also but a new company policy has made it mandatory to move to Outlook. IT has been instructed not to service Tb errors or service requests! (Not that Tb threw up ANY errors while I used it.) :(

Aristarkhos January 5, 2010 at 10:06 am

I forgot to leave the link to the tool. Sorry.

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