Open OST files into Thunderbird

Updated on October 25, 2022 by Savita Sharma

Looking for safe and easy solution to Open OST file into Thunderbird mail client, you are at right page. On this page, you will learn how you can use your OST files in Thunderbird. Microsoft Outlook is a mail application that stores its file in OST format, and Thunderbird is a mail client that uses an MBOX format file. So these both have different file formats no need to worry; you can easily use your OST file in Thunderbird. Before discussing the method, let us briefly discuss the OST file and MBOX file of Thunderbird.

Offline Storage Table (OST)

OST file is an offline copy of the user’s mailbox stored on the Exchange server. It enables the users to access all the data stored in the mailbox when the Exchange Server is unavailable. OST files stores complete mailbox including emails, contacts, drafts, notes, calendars, etc.

Thunderbird (MBOX File)

Thunderbird is an email client which stores its file in MBOX format. Multiple email clients save their files in MBOX format, and Thunderbird is one out of them. It is an open-source and free email client that easily saves entire mailbox data. Thunderbird can be used on multiple platforms like Windows, Mac, Linux, and Ubuntu operating systems.

Reasons Why User Import OST to Thunderbird:

Cross platform support: Thunderbird is a type of cross-platform mail client that can be used on multiple platforms like Windows, Mac, Linux, and Ubuntu operating systems. Thunderbird is the default client of Ubuntu.

Secure: It has high security features as compared to other email clients

Small user/Organization: If a user/organization has less dealing through Email, then they may shift from a paid email client to a freeware Email client.

User can use the Export option inbuilt in Outlook for exporting the OST file. Still, it is not considered a convenient method for migrating because it does not assure conversion insecure manner. So you can use Third party tool for complete and accurate migration of OST files into Thunderbird email client. One best-recommended tool which is easily affordable with all the advanced and required features is Regain OST to MBOX Converter. This tool can migrate OST files without the installation of Outlook.

Open OST files in Thunderbird using Regain OST Converter

Conversion of OST mailbox is very easy by using Regain OST to PST converter. Using this tool you can convert OST file to MBOX/EML file format and the converted files can be easily accessed in Thunderbird. Steps to be followed for converting OST file are:

  • 1) Install and Run Regain OST to PST Converter on Windows Operating system
  • 2) Click on Add file/Add folder and select the OST files
  • Import OST emails into Thunderbird
  • 3) Take Preview of OST file before migration in other format
  • 4) Select location for saving the file after conversion
  • 5) Next from saving option select ‘save to MBOX/EML’ option
  • Open OST file into Thunderbird
  • 6) Click Convert, files will be exported shortly.

Additional Features of OST to PST converter

  • Instantly convert OST files in few clicks
  • No loss of data and maintains the original format of the data
  • Efficient to repair corrupt OST file and recover deleted or lost OST emails
  • Compatible with Microsoft Outlook 2019, 2016, 2013, 2010, 2007, 2003, 2000, 2002, 98 and 97
  • Export OST files in multiple formats PST, EML, MSG, MBOX, HTML, ICS, VCARD, Office 365, Live Exchange Server
  • Supports all windows edition i.e. Windows 10, 8.1, 8, 7, XP, Vista
  • Detailed preview of emails before conversion
  • Allow to Import OST data files to Office 365 account
  • Easy handling of bulky files
  • Download free trial version and Save 30 emails per folder at Free of cost


On the above page, we have discussed how one can run his Outlook OST files into Thunderbird mail client. Data stored in OST format is important for every user, so no one will compromise with their data. If anyone can compromise with their data, then the export option of Outlook can be used, but the first and last recommendation of every expert is to use a third-party tool. One can use reliable software i.e., “Regain OST to PST converter” this tool is straightforward to use and provides results in very less time.