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I'm trying to transfer the locally stored emails from KMail 4 on an old computer to Thunderbird 9 on a new computer. I'm aware that KMail uses maildir format and Thunderbird uses some variant of mbox. So I thought I should be able to convert the maildir files into mbox format using some open source tool:

  • This Python script fails to run because of numerous OSErrors (different parts of the code make different assumptions about the working directory so it tries to create files in nonexistent directories)
  • This Perl script does nothing - it runs, but the folder it creates is empty
  • This Bash script apparently does create the mbox files, though I can't verify 100% that its output is correct.

Then I tried copying the mbox files into Thunderbird's profile directory. When I opened Thunderbird (version 8 with a testing profile, I believe it should work the same), the folders appeared but no messages showed up in them. I also tried importing the mbox files using ImportExportTools but the effect was the same: the folders show up in Thunderbird but the messages don't.

I've heard recommendations to use an IMAP server to transfer messages but I'm seeking alternatives because these computers are behind a rather slow internet connection.

Is there a method that actually works which I can use to transfer these emails from KMail to Thunderbird 9 without sending them over the internet?

share|improve this question
What is your OS? – soandos Dec 25 '11 at 9:27
KMail is on Kubuntu, I forget which version but it might be 9.10, and Thunderbird is on Windows 7. – David Z Dec 25 '11 at 20:07

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