Methods used to Convert Thunderbird Emails to Outlook There are two methods first one is the manual method and the second one is using eSoftTools Thunderbird to Outlook Converter. In this blog post, we will discuss the best methods used to migrate Mozilla Thunderbird to Outlook. To migrate Thunderbird emails to Outlook firstly you need to convert thunderbird MBOX file into PST Outlook format. Small and large companies prefer to use Outlook for business purposes because of its advanced features and friendly interface. Thunderbird and Outlook are popular email applications.