How to Export Thunderbird Emails to Outlook?

Summary: In this post, you’ll learn methods to export Thunderbird emails to Outlook on Windows or Mac. It details a direct method to export Thunderbird MBOX files to Outlook importable PST file using an MBOX to PST converter tool and three other methods to export Thunderbird emails to Outlook.

Mozilla Thunderbird is an open-source email client which stores emails and other mailbox items in MBOX files. However, Microsoft Outlook doesn’t support the MBOX file format. Thus, if you want to export emails from Thunderbird to Outlook, you must convert the MBOX files to PST file format.

Personal Storage Table or PST, also known as Personal Folder, is an Outlook data file that you can import in any Outlook account on Windows or Mac. It’s the most reliable way to export Thunderbird emails and other mailbox items to Outlook with precision and consistency.

Methods to Export Mozilla Thunderbird Emails to Outlook

Here are a few methods that will help you export your emails from Thunderbird to Outlook on Windows PC.

Method 1: Drag and Drop Messages from Thunderbird to Outlook

This is the easiest way to copy Thunderbird emails to Outlook. The steps are as follows,

  1. Create a new folder on Desktop and open Thunderbird
  2. Select all the emails you want to export to Outlook using Shift or CTRL key
  3. Then drag and drop the selected emails to the new folder on Desktop
Save Thudnerbird mails as EML files and export them to Outlook
  • This will save the emails in EML format. You can now open Outlook
  • Then select all the mails in the new folder on Desktop and drop them to the email folder of your Outlook account

Alternatively, you can open both email clients side-by-side and drag/drop emails from Thunderbird to Outlook.

Drag and drop Thunderbird email files to Outlook folder

However, this method is least reliable when you have to export hundreds or thousands of emails from Thunderbird to Outlook. In this process, Thunderbird or Outlook may freeze or crash, which can cause further issues such as corruption and data loss.

Further, you need to create a new folder tree structure in Outlook before exporting the mails from Thunderbird. Also, emails and attachments are inconsistent and may not open after export.

Method 2: Use MBOX to PST Converter Software

To avoid data inconsistency issue, you should use an MBOX to PST converter software such as Stellar Converter for MBOX. The software exports Thunderbird emails to Outlook PST along with other mail items such as calendar, notes, contacts, etc., with consistency and accuracy.

The steps to export Thunderbird emails to PST are as follows,

  • Download, install and run Stellar Converter for MBOX on your system
free download
  • From the drop-down, choose Thunderbird
Choose MBOX Client
  • Click on ‘Select Identity’ and browse the Identity folder that contains Thunderbird MBOX files. The path is C:/Users/YourUserProfileName/%AppData%\Thunderbird\
  • Then select the MBOX file(s) from the list and click ‘Convert’
Preview MBOX mail items
  • The software lists all Thunderbird email items after conversion. You can preview all emails to check the content and attachments
Choose Format as PST

NOTE: You must activate the software to export the converted Thunderbird MBOX files to existing Outlook PST or new PST file.

  • Close MS Outlook, if running and click ‘Save Converted File’ at the top Menu bar
  • Select New PST from the available options and click ‘Next
Browse save location to save PST file
  • Click ‘Browse’ to choose a save location. You can select drive volume on your PC or external drive. Then click ‘Save
Outlook for Mac Import PST Wizard

This will save the MBOX emails to PST format which you can import into Outlook account via Outlook Import and Export Wizard.

Import PST on Outlook for Windows

Method 3: Export Thunderbird Emails to PST by Using Gmail Account

This method works when you have IMAP settings enabled in Gmail. To export Thunderbird emails to Outlook using Gmail IMAP server configuration, follow these steps.

  1. Add Gmail account to your Thunderbird Mail client that contains emails which you want to export to Outlook
Sign in using Gmail account to thunderbird
  • Select all the emails that you want to export to Outlook from Thunderbird and copy them to Gmail Inbox or Drafts folder
Drag and drop thunderbird email boxes to Gmail IMAP account
  • Repeat these steps until all emails are copied
  • Then open Outlook on the system and add the same Gmail account to Outlook
Add an email account to Outlook - Office Support
  • After sign in, all Gmail folders will sync. This will load all the Thunderbird emails that you copied to Gmail’s Inbox or Draft folder
  • Now select all the Thunderbird emails from Gmail folders and copy them to your Outlook account folder

All emails from Thunderbird can be exported to Outlook by repeating these steps. This could take some time as mails sync between the server and the local client.

NOTE: Gmail limits attachments and thus, not all attachments can be imported. If attachments are important, either download them manually or use Stellar Converter for MBOX software.

Method 4: Convert Thunderbird Emails to PST Using Gmail Loader

You can also export emails from Thunderbird to Gmail by using Gmail Loader. You can use this free tool to import all Thunderbird emails in MBOX file into your Gmail account and then add the same Gmail profile in your MS Outlook. Then use Outlook Import/Export Wizard to export the imported Thunderbird emails to PST.

Import mail into Gmail with the Gmail Loader -

The steps are as follows,

  • Download and extract the Gmail Loader on Desktop
  • Double-click on the gmlw.exe file to launch the Gmail Loader application
  • Under ‘Configure Your Email File’, click on the Find button
  • Browse the Thunderbird email folder that contains MBOX files and click ‘Open
  • In File Type, choose MBOX (Netscape, Mozilla, Thunderbird) option
  • Then select the Message Type from the drop-down. You can choose either Inbox or Sent folder for export
  • Enter your Gmail ID in Enter Your Gmail Address field and click Send to Gmail button
  • After this completes, add the Gmail ID to your Outlook account on Windows and let it sync the folder that contains the Thunderbird emails
  • Then open ‘Outlook Import/Export Wizard’ and export this Gmail folder containing Thunderbird emails to PST format


Though you can export Thunderbird emails to Outlook via Gmail IMAP server and copy Thunderbird emails to Outlook by drag ‘n’ Drop methods, data consistency remains a challenge. These methods can help you export mails but the original tree structure, data, and attachments may not be imported. This could result in incomplete mail export, poor mail management, and data loss. Not to mention, these methods won’t export other mailbox items such as contacts, notes, calendar, etc.

Thus, if you need to export Thunderbird emails to Outlook, it’s better to use an MBOX to PST converter tool such as Stellar Convert for MBOX. As Outlook supports PST file, you can export Thunderbird mails with original tree structure and consistency along with all the attachments.

And in case your Outlook account already connected to PST file, you can append the Thunderbird emails to this PST file. Also, with Technician version of the software, you can export the Thunderbird mail items to Office 365 directly, if you use Outlook 365.