How to import Kmail into Thunderbird (and vice versa)

Now this should get some hits, once Google puts me back on the index. By the way, if you find this text useful, please don't hesitate to link to it (so that Google etc. will keep on finding this post, and the rest of my blogspot).

For those of you who like to misstype: thunderbrid kmial thundrebird tunderbird thundrebrid mkail good luck!

Millions of Windows users fed up with the poor performance of both Explorer and Outlook convert /have migrated to Firefox and Thunderbird. To do this is very well explained here for Outlook mails and addressbooks. To import Kmail mail, you only find this, which wasn't very useful to me.

I have been a fairly happy Kmail user for almost 5 years, but I wanted a change. What bothered me most was a small problem I had in Kmail 1.4, which was solved in 1.7, but for which I had to update KDE alltogether. I upgraded the OS (to get KDE 3.3), but when I found that some messages I had moved from one account to another had lost their heading (sender unknown etc.), I didn't want to switch again. Also Thunderbird allows you to make RSS accounts, and it filters the incoming messages on the server already (so they pop up as unread messages not in the Inbox folder, but in e.g. Personal-Friends-Richard in case you have a Richard-filter).

But... 5 years of emailing, all neatly organized in folders under Kmail, how to transfer that? I had once transferred from Netscape mail to Kmail, but that I did largely manually, something I wasn't looking forward to. One particular mail-folder had about 20 subfolders, and I wasn't going to make twenty directories or whatever.

Turned out I didn't have to. I am not sure, but I think the key to the success was that the Folder Type in Kmail was always "mbox" and not "maildir". To see this, in Kmail right-click a mail-folder, and look at "Folder Type- Mailbox Format". Here I had mbox (you can set this when you have a new folder, afterwards you are stuck with this as far as I know (but Google on how to alter this to see if it can be done)). [update: to convert an maildir mailfolder (e.g. Richard) to mbox, you have to make a new mailfolder, check type to mbox, give it a name (e.g. Rich) then move all the mails in the maildir folder (Richard) to the new mbox type folder (Rich). Now you can remove the maildir folder, and rename the mbox folder (Rich) to the name you had in the first place (Richard). Perhaps some wizzkid can write a script for this, but otherwise you have to do this for each mailfolder.]

What I needed to do, was to make the main mailfolder structure, but not the subfolders. With this I mean I had to make a directory Personal (and an empty file called Personal: make it, and save it (empty)), and a subdirectory Friends (also here, make the empty 'Friends' file), but not twenty subdirectories with all my friends' names in the subdirectory Friends. I only had to copy the mailfiles, and the rest was done by Thunderbird. Vice versa it worked on the same principle.

So, my Kmail mail I found here: ~/Mail/ and my Personal Directory here: ~/Mail/.Personal.directory/ This directory, therefore, doesn't show up if you do a simple 'ls'. You need to do 'ls -al' to see these files.

The mailfile for Richard was here: ~/Mail/.Personal.directory/.Friends.directory/Richard
"Richard" here contains all he mails I had saved concerning Richard.

To move this mailfile to Thunderbird, I needed to make the Personal-Friend directory structure, but not more.

Thunderbird's mail is in a funny named place: ~/.thunderbird/[randomstuff].default/Mail
In this directory I found the directory "Local Folders", which is what you also see in Thunderbird itself (I want my mail stored on the pc, not on the mail-server).

Where Kmail uses .Name.directory, Thunderbird uses Name.sbd. So, under the directory Local Folders I made the Personal subdirectory (and an empty file called Personal), and Friends as a subdirectory of Personal (and an empty file called Friends), and there I copied Richard. So the file "Richard" is at ~/.thunderbird/[randomstuff].default/Mail/Local Folders/Personal.sbd/Friends.sbd/Richard (sorry for the line-break caused by the space in "Local Folders").

And so I copied about twenty mail-files over to the Friends.sbd directory. When I started Thunderbird, all was there in the same structure I was used to (Thunderbrid generates msf-files, like Richard.msf, but just ignore those, they don't bite).

When you look into a Kmail mail-directory, you will find the Richard file, but also .Richard.index, .Richard.index.ids and .Richard.index.sorted. In the process I inadvertedly deleted those dot-files (.Richard.etc.....). As I wasn't sure Thunderbird would really work flawlessly for me (it has thusfar), that is not what I had in mind. But copying the mail-files in this now empty .Friends.directory/ directory worked! Kmail took its time, but it generated all those deleted dot-files for me! Which means moving from Thunderbird back to Kmail takes about the same effort!

Actually, if you know what you are doing, you could put links in the mail-directories. This means that using either Kmail or Thunderbird, you only change one and the same mail-file. But I didn't do this as A) I don't _want_ to use both mail-tools, B) Kmail starts to warn you it doesn't understand what is going on and in trying to do so information might get lost, and C) why not duplicate your mail now. At least you have a backup of all the mail until now. That is a start.


Now that you have, perhaps, done an import of linux kmail mail into thunderbird (convert kmail to thunderbird, or convert thunderbird to kmail), let's migrate the addressbook as well. For this, open the addressbook, and export it in ldif-format (file-->export-->Export LDIF Addressbook). This you can then import in Thunderbird (Thunderbird-->Tools-->Addressbook-->Tools-->Import-->Address Books). Worked for me.


If something wasn't clear, or didn't work, or is flatout wrong, please leave a comment (also when this text has been posted some time ago, I will get notified, read it, and if need be do something about it).