1866675 - Improve robustness of tool to import mail from Thunderbird profiles

Status: UNCONFIRMED

(MailNews Core :: Import, defect)

Description

[u738906]

Steps to reproduce:

Thunderbird 115.5. Source account is IMAP. Profile folder was copied wholesale from another machine running the latest version of Thunderbird.

Open Tools menu, choose Import.
Choose Import from another Thunderbird installation.
Choose a profile folder.
When choosing what to import, deselect everything except Mail Messages.
Choose Start Import.
Choose Finish

Actual results:

These results are consistent across import operations and have been experienced over a long period of time using many Thunderbird versions on both macOS and Linux.

Thunderbird restarts as expected.
New mail messages are imported to Thunderbird Import local folder and maintain the original folder heirarchy.
However:

1. Spam that had been manually or automatically moved to the Junk mail box on the source machine is imported with the Inbox folder as well as the Junk folder.
2. Some emails are duplicated. This varies depending on unknown factors but can be as few as 5-10 and as many as the contents of an entire subfolder.
3. Some emails are imported in a broken state. This displays as a collection of emails dated the day (and often the time) of the import, often with no subject header, always with no sender. The email when opened will be incomplete and consist of fragments of the complete email, most often displayed as chunks of HTML. The remainder of the email will be somewhere in a truncated state in the destination folder but judgment or comparison with the content on the source machine will be required to determine exactly which emails have been corrupted. They will then have to be manually exported using the Save As… function from the source machine and imported on the destination.

I can supply a redacted copy of a broken email message but would like to submit it securely for privacy reasons. Please advise.

Expected results:

The content of the Thunderbird Import folder should exactly reflect the content and structure of the emails and folders as they were stored and viewed on the source machine and given users confidence that their import is complete in every respect.

Comments:

Personally I would like to see robust checks (e.g. checksums) being programmatically applied during import to verify that all a user's emails have been successfully imported, that no duplicates are present and that mail moved into subfolders is only imported to those subfolders.

Unfortunately at present (and in fact for a few years now) importing emails has been an unreliable and therefore stressful and time-consuming process. And there's always the concern that the problems highlighted in this bug report are only the ones that I have become aware of, and that others may exist that will only come to light when a particular email is sought and found to be unavailable at a later date when it can no longer be recovered.

Comment 1

[u738906]

Obviously I'm disappointed there's been no apparent action on this bug report, but I accept that the feature I'm reporting about may not be a high priority.

If someone could respond with a reliable workaround that I can deploy until this bug report is addressed it'd be appreciated. I have an increasing stockpile of emails to import and, frankly, the knowledge of how much time it would take to perform with any sense of confidence in the outcome makes it a task I don't particularly want to perform.