Developer reply by Christopher Leidigh
Rated 1 out of 5 stars
Importing eml files to thunderbird local folders will break attached files (can't open, can't download) which is quite serious as a problem
lorenzo997
It's not totally clear what is going on from your post.
Can you post the problem in the repository where I can help resolve this.
Christopher
https://github.com/thunderbird/import-export-tools-ng/issues
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