ThinkGeek - Cool Stuff for Geeks and Technophiles

March 30, 2004

OT ( and rant ): Switching from Thunderbird to Outlook

After almost a year of being a happy Thunderbird user, I've been forced to switch back to Outlook. And it's been a real pain.

When I switched to Thunderbird, it took me five minutes to import my e-mails, addresses and rules from Outlook into Thunderbird. It was just a question of a few clicks.

But yesterday, everything was different. First, I couldn't find the "Export button" in Thunderbird. So, after reading the faq's, I discovered that the format of the mail folders is the standard Unix mail format ( "MBox" ), so that I could import my email from Outlook, using the "import from Eudora" assistant. Obviously, it didn't work. I constantly received error messages, telling me that the mail folders were in use ( when they weren't, I had all permissions for those folders, every Mozilla program was closed, ..)

So, back to google, I found an utility called MBox2eml, that allows to export mailboxes from the MBox format to eml ( the Outlook Express format ). This utility worked well, except for the fact that it failed when trying to transform a high number of items. So I was exporting my emails, 100 at a time.

Then, I exported my emails from Outlook Express to Outlook. Everything seemed to work right ( I have not checked the attachments yet ), but the whole process took me about three hours!!. Three hours to complete a process that should have been finished in only five minutes.

I'm not going to blame only Microsoft, but also Mozilla. I think it's obvious that switching to Outlook from Thunderbird should be as easy as the opposite. But, at least for me, it wasn't easy at all.

Posted by Cesar Tardaguila Date: March 30, 2004 12:26 PM | TrackBack

Forced? Why's that?

Obligado? Pq?

Posted by: GaBuBu en: March 30, 2004 01:13 PM

well, in some sence it should transfer both ways, but realy i doubt that feature is in high demand, after all most people only use ms products because they are bundled and once they find something decent they tend to stey on the better app

Posted by: DevilDude en: March 30, 2004 01:22 PM

I dont'know... don't know...

If OE doesn't have an "Export to...", why shoud Moz have one? It's hard to migrate Moz to OE (or O) because M$ wants it. Moz have its importer (from various sources) and it works fine... the question should be: why OE (or O) doesn have one? ;)


Posted by: ala_747 en: March 30, 2004 02:38 PM

Well, the point is that I want to be able to switch from one e-mail client to another when and how I want. And I also want to be able to switch from one browser to another.

Sometime ago, I also switched to OpenOffice. After some time I had to move back to Office, and I didn't found a single problem

Obviously, not many people will have exactly the same problem I had yesterday ( and, in fact, when I switched to Thundebird I thought I will never see Outlook again ), but who knows?.

What I wanted to say was: Shouldn't we, as users, be allowed to easily choose which software do we want to use?

And, FYI, I was forced to move to Office at work, not at home, where I am still a happy and loyal Mozilla and OpenOffice user. ;)

Posted by: Cesar Tardaguila en: March 30, 2004 03:10 PM

My suggestion: IMAP. I switch clients every now and then (I happen to love thunderbird too), and having all my mail stored on the server ROCKS.

Posted by: Steve en: March 30, 2004 03:12 PM

Switching back to the dark side of the force? Why?
It's a bit curious that there is no app or protocol to store the addressbook on a server. IMAP is really great but doesn't allows me to have an online addressbook or calendar or am i too blind to see the solution?

Posted by: Roland Schaer en: March 30, 2004 04:14 PM

It sounds like one of the mozilla components could have been still loaded in memory when you were trying to import to Outlook.

Even though you close all instances of Mozilla or Thunderbird, it stays in memory so it starts up faster next time. You can kill it through task manager and there is an option somewhere to tell it not to stay in memory.

Just a thought.

Posted by: Spike en: March 30, 2004 07:20 PM

Yeah, I thought so, so I even uninstalled the whole suite, after scanning the task manager, but...

Posted by: Cesar Tardaguila en: March 30, 2004 07:32 PM

Oooooops!!! Thanks for the tip, anyway!

Posted by: Cesar Tardaguila en: March 30, 2004 07:33 PM

No I totally agree..
I've had the same problem.. Very annoyed by a couple of minor irritiating things with Thunderbird.. Went to switch back to OE, and no easy export facility. Wasted plenty of time on this too - thanks Mozilla.

Luckily I found your post and downloaded that java utility - worked great for me..

Note: One thing I found useful too.. Right click on each folder inside Thunderbird and select "Compact this folder" first, because the mbox format stores all the deleted messages just flagged as "deleted" - hitting this option removes them so that the java utility does not import all your old deleted messages! :)

I just dragged the resultant .eml files into appropriately named folders inside OE - worked a treat..



Posted by: cisco en: April 11, 2004 05:08 PM

Thanks for the tip, Aaron!

Posted by: Cesar Tardaguila en: April 13, 2004 10:41 AM

Guys, What is this java utility you guys are talking about. Where can I found it. Do you think it will work with a Mozilla to Outlook conversion.. not Outlook Express?


Posted by: Dave en: April 15, 2004 01:43 AM

Hi, Dave.

The link is in the post, but, here it is again:

Posted by: Cesar Tardaguila en: April 15, 2004 10:04 AM

I just built a new computer and am in the process of moving everything to it, this includes my existing Thunderbird messages and my account settings.

I think it is downright lame that there is no export feature built into Thuderbird. The FAQ on "How to Export messages" is terrible at best. If anything, we should be able to export messages in a standard format. Move those exported messages to a new machine and import them to our new Thunderbird.

I found it was easiest to literally copy/paste the profile folders directly to my new computer, then I had to manually re-send each email I wanted to keep back to myself. Obviously, any more than 10 emails, and this is an incredible hassle.

Posted by: justin en: April 23, 2004 08:34 PM

You should post some warning that you will display my email address if I don't provide a URL, please remove my email address from this page.

Posted by: justin en: April 23, 2004 08:36 PM

Hi, Justin.
From the MT manual:
"If the spam_protect attribute is provided, and the email link is to be displayed, the email address will be modified so as to prevent spambots from harvesting it. The web browser, however, will still display the email address properly. "

Anyway, I've changed your first comment e-mail address. If you feel that's not enough, just tell me and I'll remove both your comments.

Posted by: Cesar Tardaguila en: April 23, 2004 11:52 PM

hey guys...

i found the EASY SOLUTION!!!!

a few simple steps...

1) goto your PROFILE dir, located in doc-settings folder (if you dont know how to find that look somewhere else i dont feel like explaining that...)

2) find your account folder that holds your inbox, sent, drafts, etc. files.

3) cool, so now here's the easy part, rename all of those files to GIVE THEM AN MBOX EXTENSION hehehehehhe...

for example:

just rename 'INBOX' to 'INBOX.MBX'

4) now when you goto your new app and try import as EUDORA it will see all of your emails!!

whew! ;)

now why couldnt they just add that to the thunderbird FAQ eh?? feel sorry for you other guys that had to take the long nasty route!! i got at least 1000+ emails and i had to find an effecient method..

anyway hope that helps,

- josh

Posted by: joshua collins en: May 1, 2004 05:50 AM


didn't work it shows 0 messages in the folder when i know damn well there's about 2500 .........

guess i'll try this java app... hopefully that works

(dont speak before its all done and confirmed! lol)


Posted by: joshua collins en: May 1, 2004 05:55 AM


i dont know why it took that other guy so long i just converted abotu 5000 emails total from mbx to .eml....

did it all in about 2minutes total!!

good stuff... i'd recommend that utility for sure


Posted by: josh collins en: May 1, 2004 05:58 AM

Where are .mbx files stored? I am having a hard time finding them, and can't really figure out how to use the mbox2eml program ( there is no step-by-step process on how to use it, at least none that I could find ). any help would be appreciated.

Posted by: Jamie en: May 3, 2004 11:05 PM

At least in my computer ( WinXP Pro ) they are located here:
C:\Documents and Settings\{user}\Datos de programa\Thunderbird\Profiles\default\ual3up11.slt\Mail\

And then , there's a different folder for each email account. My system is aspanish, so you should change "Datos de programa" by "Application data" ( I think ).

Posted by: Cesar Tardaguila en: May 3, 2004 11:13 PM

Thank you for information !

Posted by: avalon en: May 8, 2004 01:28 PM

Hi, I have installed on my computer Conectiva Linux. It's a variable of Red Hat Linux. My e-mail client is Mozilla. I need to export to Outlook Express my mails. How I do that?
Thanks. Moisés.

Posted by: Moisés en: July 26, 2004 04:56 PM

I tried TB too, and just like all you guys didnt like it, so now getting back to my old Outlook03. I think i'll try to use this utlitity from home tonight and see how it goes. From the looks of it, everyone is happy with the utility, so should be fine.

There's one question bothering me, After running the utility, you have the .eml files on your Hdd, so why drag them to OE, and then import in Outlook, why cant we simply drag to Outlook03? Or am i missing something here?

Posted by: Monty en: August 27, 2004 01:52 AM

Hi, Monty.

Well, I don't remember if I tried to drag the -eml files to outlook 2003 directly, but if you try it, and it works, let us know!

Posted by: Cesar Tardaguila en: August 27, 2004 12:13 PM

I'm *really* glad I found this page. I, too, want Outlook back. However, I'm a bit dimwitted and cannot find the folders where Outlook Express keeps its mail files. Where is it?

I've converted my Thunderbird files to eml files--a folder each for Inbox, Sent, etc. But where do I go from there? I would really appreciate a bit more detailed instructions.

P.S. -- I've never used Outlook Express, only Outlook. Sorry for the ignorance.

Posted by: ZenWarrior en: September 16, 2004 06:10 PM

I took the link from Cesar, and the advice from Josh, and got all my messages into Outlook. Rename the Thunderbird files to .mbx, and then run the mbox2eml.jar. Then click and drag them in. Done deal. Thanks guys.

Posted by: MDB en: September 22, 2004 03:53 PM

Outlook Express stores all of it's files in a folder, you can see it under the maintenance options - there is the path to it, you can just back up or copy the files in that folder and if you need to import them in a different Outlook Express installation, just copy them to the same folder and when you launch it, it will resotre all the folders and the messages.

As to moving messages from Thunderbird to Outlook Express - the mbox2eml program worked fine with about 100 messages to move. Create .eml files, CTRL+A select them, drag them in your Outlook Express inbox and you are set. If you need them to Outlook, after this, open it and do a regular Import from Outlook Express 5.x 6.x etc.

Posted by: mxz en: October 19, 2004 10:15 AM

i switched from thunderbird to outlook 2003. i just like it better. lots of great features. beauty is in the eye of the beholder, no?

what a pain to get my messages out of thunderbird - an oversight or arrogance? anyway, thanks to all who posted such helpful comments.

Posted by: tom en: October 26, 2004 06:40 AM

> This utility worked well, except for the
> fact that it failed when trying to
> transform a high number of items. So I
> was exporting my emails, 100 at a time.

I imported more than 2000 Thunderbird emails without a problem! It appears to freeze at first (doesn't respond to mouse clicks, and windows appear to freeze to), but I just let it do it things and left my computer idle for about 15 minutes or so.. when I come back all my emails are converted! Tadaa!

Thanks for your blog, I succesfully imported all my Thunderbird mail.

Posted by: rosdi en: October 31, 2004 11:05 PM

Another alternative is to use IMAPSize (

IMAPSize has conversion tool (eml2mbox and mbox2eml) that doesn't choke even though you have huge emails. I have ~4000 emails in my mailbox and IMAPSize works like charm!

Posted by: Rosdi Kasim en: October 31, 2004 11:50 PM

What a dreadful experience... Big thanks for all the helpful peeps who have posted info here, without you I would have been lost!

I find it appauling that MS Outlook 2003's import functionality is so poor!

Once I had converted my Thunderbird mail into eml files, it couldn't import them - dragging the eml files from explorer into Outlook 2003 didn't work properly either as it just saw them as 'attachments' & used Outlook Express to open them!

Even after dragging the eml files into outlook express, outlook 2003 couldn't import my messages, it couldn't find my outlook express profile!

Eventually I used the outlook express export feature, to push my mail into outlook 2003. (If anybody wanted a step-by-step guide of how the whole process works, I think you've just gotten it - except for the part of converting thunderbird files to eml files that is!)

What a palaver! Anyway, thanks again for the link to the Java 'mbox to eml' utility & all the other informative posts!

Posted by: Matt en: November 5, 2004 08:44 PM

Thanks for the link. mbox2eml works like a charm.

As for the Thunderbird export: I consider using the multi-platform mbox format sufficient. All my data is automatically exported, essentially. I'm *extremely* disappointed in Outlook's import functionality. According to my Googling, the biggest problem is that Outlook isn't building an index for the mailbox. But if Eudora can do it (which it does automatically), and some 3rd-party Java utility can read the format with no problems, why can't great big M$ do it?

When we transfer the other way, we don't ask Microsoft why we can't import into Evolution, do we? Why would we ask Thunderbird why we can't import to Outlook? It's an MS problem.

Posted by: judebert en: December 1, 2004 03:39 PM

How do I transfer my address book to Outlook?

Posted by: Kaurik en: December 17, 2004 09:39 AM

Thanks for the link to IMAPSize. Did the job in about 5 minutes. Only been trying out Thunderbird for a couple of days when I hit a showstopper concerning sending attachments so didn't have too many files to convert.
Converted files from TB and then dragged them into Outlook Express with no problems.
Goodbye Thunderbird!

Posted by: ANZO en: January 4, 2005 08:05 PM

This site - - explains how to do it.

Posted by: Alex en: January 17, 2005 09:37 AM

Alex said:

This site - - explains how to do it.

That link may have worked for a while, but now it's a dead end....

Posted by: CDU en: April 14, 2005 06:54 PM

check the link

this explains Export mail into Outlook

Posted by: Sujith M. Nair en: April 18, 2005 08:43 AM

That program works great, but I am finding one down fall. The email dates are all today.

Posted by: summerstupid en: May 17, 2005 06:56 PM

What a hassle! However, I am another one of those needing to go back to Outlook and have found this posting very useful. I am running the IMAPSize program that is running like crazy converting the files. It took a while to just select the files to convert since I had them in many different folders and subfolders and you need to find each one separately to select it and then include it in the convert file table. I do not use Outlook Express but I guess if there is no other way, I will have to open it, configure it, import the files and then convert/export them to OUTLOOK 2003. Am I correct? I hope so. Thanks again to all of your for this great posting. JAVIER

Posted by: Javier Sotomayor en: May 27, 2005 06:31 PM