With the help of MacSonik Thunderbird Backup Tool to save Thunderbird emails into different file formats like PDF, PST, EML, EMLX, DOCM, DOCX, PNG, JPG, MSG, HTML, MHTML, GIF, etc. It can back Mozilla Thunderbird emails to 20+ formats and its prominent feature of Eliminate Duplicate Email is outstanding. Using this feature you can remove the identical emails from the backup process of Thunderbird emails.