Rated 5 out of 5 stars

Same problem as Mark Acosta.
Exported Mails from a .pst via Outlook Viewer to .eml files and tried to import them with your addon. It just imported the folder structure but not the mails itself.
Reverted Thunderbird to 60.9.0, used the old addon and it worked.
Not trying to sh*t on your hard work, thanks a lot for trying to port the addon.
Will edit the review when the problem is fixed.

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Update 10.2019
Thanks for adressing the mentioned issues. Haven't had the chance to try your fix, but other reviews seem to confirm your fix is working. Updated the review as mentioned before.

This review is for a previous version of the add-on (4.0.2). 

Can you let me know if you have had success with 4.0.4?
If there are still problems I would like to know.

Have you tried the 4.0.4 update? it should take care of both import and export issues. if it looks good it would be great update the review

TheRealStaff/Mark
Thanks for the issue report!
Unfortunately I got between unannounced deprecations with point provisions to TB.
I have a beta that addresses EML subfolder import. Prior 4.0.2 addressed attachment export.
I want to do some more regression testing then will submit. Any feedback great
I don't have Outlook currently so I export/reimport to test EML. GH beta pointer:

https://github.com/thundernest/import-export-tools-ng/blob/master/xpi/import-export-tools-ng-4.0.3-b1-tb.xpi