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Need to migrate email between Outlook and Thunderbird

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Last Modified: 2020-02-20
I'm looking for a way to move email I have in an Outlook *.pst file to Thunderbird that actually works.

I used to use Outlook for personal email, which I kept in a *.pst file.  The company policy has changed however and I cannot use Outlook for personal email any longer.

My personal email is Gmail and Thunderbird has been a long-time supplier of a solid email product so I installed that and it works fine, however I have thousands of email in a hierarchy of perhaps a hundred folders I need to move over.

I've tried uploading to gmail folders from Outlook on another computer, however that's a complete joke.  Files don't show up.  The equivalent of folders in email don't get created.  Just a disaster.

I've downloaded a thunderbird extension for import, however it fails while throwing windows errors.

I have yet to find a program that can move the email (and the folder hierarchy) into Thunderbird, so I'm writing to see if anyone can recommend one that will actually work.  Free or otherwise.
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Jim RiddlesPrepress/OMS Specialist
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Commented:
I don't have personal experience with Thunderbird, but a quick search leads to this article.  I don't have time to paraphrase the steps here right now, but have a look and see if it does what you need.
How to Import a PST File in Thunderbird | Techwalla.com
Bill PrewTest your restores, not your backups...
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Commented:
I haven't poked at Thunderbird in a while now, but I do recall a product that a peer used once to convert PST content into Thunderbird.  It was years ago though, so I don't recall the details, and I'm sure the product has evolved, but I do remember it accomplished what they needed at the time, which sounds similar to what you mentioned.

I can't provide much more than that, sorry, but here is the product they used and I think it was free at the time, so maybe just  the "Home" version is enough...



»bp
David FavorFractional CTO
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Commented:
https://www.experts-exchange.com/questions/29158183/Backloading-emails-into-gmail.html provides a dirt simple way of doing this.

One option for large volume mail.

One option for small volume mail.

Note: Keep in mind Outlook + Thunderbird are both clients. The failsafe way to migrate mail is by focusing on the IMAP server side, not the client side. If you follow the above URL instructions, makes no different what client you use, you'll see the exact same IMAP server in any number of clients after your migration.
Gene KlamerusTechnical Architect

Author

Commented:
@David

I've tried uploading the *.pst file (which is attached to my Outlook client) up to gmail and it's an utter failure.  It doesn't copy nearly half the email and also fails to copy the folders in which the email sit.  Essentially the entire scheme that Google has for organizing email is really pretty poor.  Everyone uses the folder metaphor and they simply don't.

I'm aware these are different clients, but if I cannot upload to a common source (ala gmail), then I also cannot download them.

Several of the popular email clients claim the ability to import *.pst file contents.  It's not a horrifically complex format.  There are tools out there to do various things with them (besides migration).  I just haven't been able to find one.

@Jim,

I've tried that procedure (which is slightly out of date).  Unfortunatley, the importer (a Thunderbird extension) fails.

Honestly if there were something that actually worked uploading to gmail, I'd go that route, but I've had other experiences in dealing with the Google tools and they often don't work properly (or require extremely robust clients - beyond what most developers create).
Gene KlamerusTechnical Architect

Author

Commented:
Sorry if it sounds like I don't appreciate the comments, but I have been trying to upload files by dragging them from the Outlook client to the gmail only to have that simply fail left and right.

The native email importer for Thunderbird (or the one I got via the add-in) just says it cannot find a default email application configured (which Outlook is).
Gene KlamerusTechnical Architect

Author

Commented:
I'm giving a tool I found called GainTools PST Converter a shot.  It was relatively cheap.  It creates mbox files.  I'm unfamiliar with that, so my first attempted put everything in one big folder (in my Thunderbird local files).  I'm letting it create more files and hoping that will represent folders for when I do the import.  We'll see.  I didn't realize I had about 50,000 email, but it runs very quickly; about 100 messages every 3 seconds.
David FavorFractional CTO
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Commented:
So... If you're creating mbox files, you still have the same problem.

No client will every be able to read an mbox or Maildir or any other backing store file... natively/locally... These files still must be served by a POP3 or IMAP4 mail server.

When using a tool like you've described, you'll have to run the tool wherever your .pst files live, which will produce mbox files, which you'll then have to copy over to some mail server (like Dovecot), then integrate all the mbox files into Dovecot.

Tip: Using mbox files is fine for a handful of mail. If you have 1,000s to 1,000,000s+ of email, use Maildir format... As mbox files can become very slow to access + easy to corrupt, with many email in one mbox file.
Gene KlamerusTechnical Architect

Author

Commented:
no, not really.   I'm able to directly import mbox files into Thunderbird.  They actually all did import.

Also, this is a one-time activity.
Gene KlamerusTechnical Architect

Author

Commented:
Well, the combo of products I went through worked out very well.

For the benefit of others, here is what I did.

I used GainTools PST converter to export the email I had and its folder structure from my PST into a directory of folders and EML files (this seems to work better than MBOX files.

Then I went to Thunderbird.  I downloaded the ImportExportTools NG extension.  I ran this to import the entire folder tree and email into my Local Folders.

I had about 24k email in total.  The export from the PST was pretty quick (2-3 minutes).  The import into Thunderbird took about 30 seconds.
Technical Architect
Commented:
I described the solution just previously.