How to Import a PST File to Thunderbird?
The eSoftTools PST to MBOX Converter Software, which can be downloaded for free, is a solid option for converting PST to Thunderbird. Exporting Outlook emails to MBOX format for later use is straightforward using the PST to MBOX Converter Software, which is cloud-based like Gmail, Yahoo, and Office 365. Only a few steps remain in this procedure. PST files can be converted to ANSI or UNICODE formats. The software works with both Microsoft Outlook 2007 and previous versions. The tool will be used by customers with little or no technical knowledge. During the free trial, you can move 25 emails from each folder.
Visit here:- https://www.esofttools.com/pst-to-mbox-converter.html
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Jacksonallen commented
To securely import PST files into Thunderbird, you can use the Advik PST Converter Tool on your Windows. This is a secure and authentic program that does not lose any single bit of data during the process. It has a dual mode that enables you to import PST file to Thunderbird in bulk. It preserves all email attributes and mailbox folder hierarchy during the process.
Read More: https://www.adviksoft.com/blog/open-pst-file-in-thunderbird-with-attachments/