robert_11
09-24-2025, 09:44 AM
Thunderbird, out of the box, does not support incremental migration from PST files. After you have imported a PST into Thunderbird (which first requires converting the PST to MBOX), Thunderbird will treat that import as a one-off import. This means that if you add new email in Outlook at a later point, Thunderbird will not know to only import the new data. You would need to import the PST again, starting from scratch with the older email, resulting in duplicates and wasting time.
Technical Solution with TrustVare PST to MBOX Converter
A better way to manage migration is to utilize a professional tool, TrustVare PST to MBOX Converter (https://www.trustvare.com/pst/mbox/). This tool provides a smooth, safe migration of Outlook PST files to MBOX files, which are compatible with Thunderbird.
Heres how it addresses incremental migration needs:
Selective Migration You have the option to select folders or date scopes to migrate, and therefore avoid migrating old data.
No duplicates The tool will avoid duplicate items every time you run the migration.
Batch Conversion, Migrate more than one PST file at one time and without size limits.
Push structure The software will maintain email formatting, attachments, and folder hierarchy.
Directly put into process The exported files are MBOX files and can be imported directly into Thunderbird.
Instructions:
Open the TrustVare PST to MBOX Converter.
Add the PST file(s).
Choose folders or use filters (like by date).
Convert to the MBOX.
Import the MBOX files into Thunderbird.
You can run this process on a regular basis to allow for an incremental-type migration (if there are filters, such as by date or if you add a PST that contains new items) without having duplicates.
Technical Solution with TrustVare PST to MBOX Converter
A better way to manage migration is to utilize a professional tool, TrustVare PST to MBOX Converter (https://www.trustvare.com/pst/mbox/). This tool provides a smooth, safe migration of Outlook PST files to MBOX files, which are compatible with Thunderbird.
Heres how it addresses incremental migration needs:
Selective Migration You have the option to select folders or date scopes to migrate, and therefore avoid migrating old data.
No duplicates The tool will avoid duplicate items every time you run the migration.
Batch Conversion, Migrate more than one PST file at one time and without size limits.
Push structure The software will maintain email formatting, attachments, and folder hierarchy.
Directly put into process The exported files are MBOX files and can be imported directly into Thunderbird.
Instructions:
Open the TrustVare PST to MBOX Converter.
Add the PST file(s).
Choose folders or use filters (like by date).
Convert to the MBOX.
Import the MBOX files into Thunderbird.
You can run this process on a regular basis to allow for an incremental-type migration (if there are filters, such as by date or if you add a PST that contains new items) without having duplicates.