To import an OST file manually to Thunderbird, convert the OST to PST through Outlook first. Next, employ a utility such as "ImportExportTools NG" within Thunderbird to import the contents of the PST after converting the PST contents into MBOX format with a DRS Softech OST to PST converter.

This is a process with more than one tool involved. Manually converting might result in data inconsistency, and attachments or folder structure could be lost. Thunderbird does not directly support OST files, so the procedure is lengthy and technically complex for non-technical users.

The Outlook data transfer to Thunderbird is almost impossible without the involvement of any third-party/external tools, as neither Thunderbird nor Outlook provides any direct option for transferring data from Outlook to Thunderbird. There are various converter software online that can be used by users to carry out the migration task, but it is always advisable to use the efficient and trustworthy solution. Hence, we propose the use of the excellent DRS Softech OST to PST converter for OST file export to MBOX format without any sort of error or loss of data.

DRS OST to PST converter is a powerful solution that enables users to export OST mailbox items in PST, MBOX, EML, PDF, MSG, AOL, IMAP, Gmail, etc. There are no file size limitations. Additionally, it opens the damaged OST files easily and then converts them into PST.

1. Open the OST file conversion tool in your system.
2. Select the single file or multiple file option.
3. Give the Log and Temporary file location then, press the Next button.
4. Now select the select file or select folder as per your need.
5. All the selected files will be included in the tool.
6. Select the Outlook OST items you wish to export.
7. Press the Next button to proceed further.
8. In the subsequent windows, check on the checkboxes as below as per your needs.
9. Specify the path to save the resultant files.
10. Click Convert to initiate the importing process.
11. After the importing process is completed, users can download the report in CSV format.

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