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How to Export Thunderbird Emails to Outlook

How to Export Thunderbird Emails to Outlook

Thunderbird to Outlook Transfer – User’s Manual

Thunderbird to Outlook Transfer icon This user’s manual covers the process of converting and transferring emails and attachments from Thunderbird to Outlook. Due to the difference in data formats used by these programs and their general approach to storing data, direct import with integrated tools or functions is impossible, and such migrations require the use of specialized conversion software like Thunderbird to Outlook Transfer. The outlook converter software automates nearly 99% of the process, but still requires some user involvement, and the article below describes it in detail. This guide also describes alternative methods which are more complicated but still useful for converting from Thunderbird to Outlook.

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Instant solution to convert Thunderbird emails to Outlook PST format and export Thunderbird messages to EML files. Download Thunderbird Converter and start your hassle-free Thunderbird migration now!

Content of this instruction:

Method 1: Using Thunderbird to Outlook Transfer tool

Additional tips

Method 2: Export Thunderbird mail to Outlook using drag and drop method

Method 3: Using Gmail IMAP as a proxy

Frequently Asked Question

How to convert Thunderbird to Outlook using Thunderbird to Outlook Transfer tool?

Following brief video shows the main steps of the Thunderbird email conversion.

Method 1: Saving emails from Thunderbird to a standalone PST file on your hard drive

If you want to convert Thunderbird to Outlook PST format ( .msf to .pst ), but don’t want to export them to Outlook right away, you can save the files to a PST format on your HDD for future use. The Thunderbird conversion software will still require Outlook to be installed on your system to convert thunderbird mail to outlook PST files.

This method requires you to have standalone Outlook installed on your system. Outlook User Profile should be configured, for that you have to run the MS Outlook after setup and follow the configuration wizard.
Thunderbird to Outlook Transfer is designed to convert Thunderbird messages together with attachments if the attachments are embedded into the messages. If additional options and flags such as read status, flagged, and chain of responses and dialogs are not stored inside source mailbox files, they will not be converted.
For successful PST conversion follow these steps:

Step 1: Download Thunderbird converter software

Download and install the latest version of Thunderbird to Outlook Transfer software on your PC. Installation normally takes less than a minute and does not require any additional components or libraries to be downloaded.

Download for FreeFor Windows 32/64-bitBuy from $24.95Unlock all features

* - The unregistered version converts a limited number of messages

Step 2: Run the Thunderbird Transfer Software

If your MS Outlook edition is 32-bit, you have to use the shortcut which launches the 32-bit conversion utility, otherwise you have to run the 64-bit tool. Both shortcuts became available at your computer desktop after the installation.

Thunderbird Transfer icons

Step 3: Locate Thunderbird mailboxes (.msf files)

The program should automatically detect the location of the source *.msf and mailbox files. If it doesn’t, click on the “…” (Browse) button and select the necessary folder on the hard drive (see “File and folder selection” for details). You can also use the File -> Open command.

Selict source folder containing Thunderbird MSF mailboxes

Step 4: Run the Folders Scanning

Click the “Scan Folder” button (Find Storages button in old software versions), the program will show a list of available folders (email containers) in the large text area in the center of the program window. You may deselect there a folder(s) which you do not want to be processed, for example, to skip the Inbox emails, you may uncheck the Inbox container.

Search for all Thunderbird mailboxes to convert

Step 5: Choose a proper Mode

On the top menu bar click on “Mode” menu  and select “Save to PST File” mode.

Mode - Save to PST file

Step 6: Close Mozilla Thunderbird and click Save PST button

Exit Thunderbird if it is still launched. Click on “Save PST“. The program will prompt you for a folder that the resulting PST file will be saved to. Select the location to save the PST file and confirm to save. This will convert thunderbird mail into Outlook data file.

Converting Thunderbird MSF emails to PST

Step 7: Conversion Complete

Wait until the program has finished processing all the files. Full details about the items being processed will be shown in the log window.

Step 8: Import Thunderbird PST in Outlook 2010/2013/2016/2019/2021 for Windows

Converted PST file can be immediately copied to another system and loaded to MS Outlook. By default Thunderbird Transfer tool opening resulting PST file in Outlook automatically. (You may disable this behavior via menu Options). If the PST file was not opened automatically you may open it manually.

    1. Run Outlook and click menu File
    2. Select Open & Export menu option
      Open PST file in Outlook
    3. Click Open Outlook Data File.
    4. Select PST file in the appeared dialog and click Open button

If Thunderbird is not installed on your system, you can still use Thunderbird conversion software. Just copy the Thunderbird data folder from any other system and convert its content into a PST file. Copy the PST file to the destination system and load it in Outlook to access the converted emails.

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Importing Thunderbird messages to Outlook

This can only work if you have Microsoft Outlook on your system. Outlook Profile should allow the direct data import otherwise imported emails will be vanished by the server synchronization. Here is what you need to do to transfer your data:

Step 1: Download the Thunderbird Conversion Software

Download and install the latest version of Thunderbird to Outlook Transfer program on your PC. The Installation is fast and easy, and does not require any additional tools to be downloaded.

Download for FreeFor Windows 32/64-bitBuy from $24.95Unlock all features

* - The unregistered version converts a limited number of messages

Step 2: Run the Thunderbird to Outlook Transfer Software

Run Thunderbird to Outlook Transfer tool. (Use the proper edition for your Outlook type)

Choose 32 bit or 64 bit icon

Step 3: Locate the source files

The program should automatically detect the location of the source files. If it doesn’t, click on “…” (Browse) and navigate to the necessary folder on the hard drive (see “File and folder selection” for details). The same can be accomplished using the File->Open command.

Selict source folder containing Thunderbird MSF mailboxes

Step 4: Scan the Folders

Once you have selected a folder and its name has appeared in the Source Folder field, click on “Scan Folder” or use the File->Scan Folder command to start searching for mailbox (mbox) files in the specified folder. The names of available Thunderbird mbox files will be shown in the large text field occupying the central part of the program window.

Search for all Thunderbird mailboxes to convert

Step 5: Select the appropriate mode

Use menu “Mode” to select the “Import to Outlook” option

Mode Import to Outlook

Step 6: Import and choose a destination folder for your email files

Click “Import” to start importing your selected messages to Outlook. A new dialog box will appear and you will need to choose a destination folder for your imported messages. Full details about processed items will be shown in the log window.

Thunderbird Import to Outlook

Step 7: Once the process is over, you can launch Outlook to access your messages.

Alternatively, if you want to export your Outlook messages, go to File > Open and export > Import/Export. A dialog box will appear and you can choose the function you want.

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Export Thunderbird emails to email files

This work even if you do not have MS Outlook on your system. Here is what you need to do to export Thunderbird emails from mbox files to EML format. The process of exporting messages from Thunderbird to files using Outlook Transfer utility is similar to the procedures described above.

Step 1: Run the Thunderbird to Outlook Transfer software.
Step 2: Specify the source folder if the program was unable to detect it automatically.
Step 3: Go to menu “Mode” and enable “Export to EML files” option.

Export Thunderbird to EML files

Step 4: Click “Scan Folder” button to scan all Thunderbird folder hierarchy.
Step 5: Click “Save EML” button, specify the target folder to save exported Thunderbird mail and confirm saving.
Exporting Thunderbird emails into files will be completed is several minutes.
Step 6: Run EML to Outlook Converter software and import EML files to Outlook.

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Additional tips for Thunderbird Migration

Locating Thunderbird mailboxes

Our products are designed to automatically detect the location of the source data files of corresponding programs. However, this is not always possible. If Thunderbird to Outlook Transfer utility fails to detect the path to *.msf data files and mailing list automatically, this may be a sign of conflicting profiles, identities, a registry corruption issue or another minor issue rendering path auto-detection impossible. It will also happen in situations when you have multiple Identities or Thunderbird mbox files are copied from another system – that is, when Thunderbird has never been installed on the user’s system.

In case the program fails to locate your *.msf emails automatically, click the “…” (Browse) button to open the standard Windows folder selection dialog and select the source folder manually.
Browse button
By default, Thunderbird stores emails in a profile folder located here:

C:\Documents and Settings\%USERPROFILE%\Application Data\Thunderbird\Profiles\XXXXXXXX.default\Mail\


C:\Users\%USERPROFILE%\AppData\Roaming\Thunderbird\Profiles\XXXXXXX.default-release\Mail\Local Folders\

Where %USERPROFILE% is your username, and XXXXXXXX is a sequence of arbitrary characters.

Please note that the “Application Data” folder is hidden by default and will not be visible in the dialog.

To make hidden folders visible, do the following:

  • Open Windows Explorer (Ctrl+E) , click on “Organize” and select the “Folder and Search Options” command from the menu.
  • Switch to the “View” tab
  • In “Advanced settings”, find the “Hidden files and folders” node and expand it
  • Enable the “Show hidden files and folders” radio button
  • Uncheck the “Hide protected operating system files” option
  • Click OK.

Doing this will unhide hidden folders and allow you to select the one containing Thunderbird source files in the manual mode.

IMPORTANT: Please bear in mind that Thunderbird to Outlook Transfer tool is capable of detecting the main Thunderbird profile location automatically if Thunderbird application is installed on the same system. However Thunderbird profile may contain several Identities and Account records. In this case it is required to select the proper source directory manually. For multi-identity configuration we recommend to process each email account separately. Thunderbird to Outlook Transfer program can extract and convert data from damaged mailbox files of all supported formats and import them into 2010, 2016, 2019 and earlier versions of Outlook.

While working on Thunderbird to Outlook conversion software, we pursued the goal of automating as many complex operations as possible, and we’ve got most of the process covered by our tool. Your role is restricted to making a couple of simple choices and confirming your selections. You have three options: direct Thunderbird import to Outlook, saving messages to a new standalone PST format, or extraction of Thunderbird mail to EML files The first scenario is fairly self-explanatory, while the second and third allow you to copy the resulting file(s) to any type of drive or cloud storage or transfer it to another system.

Download for FreeFor Windows 32/64-bitBuy from $24.95Unlock all features
* - The unregistered version converts a limited number of messages

Check the Location with Thunderbird email client

If you still have the Mozilla Thunderbird installed at your computer, you may use menu Options | Account Settings | Server Settings to check the location of the email message store. The value of the field “Local Directory:” is what you need.

Step 1: Locate the email files

Run Thunderbird and click Options > Account settings

Thunderbird account settings

Step 2: Click on Server Settings

On the next page, click on server settings. On the Local Directory part, you will see the location of your Thunderbird emails.

Thunderbird local directory

Select and copy the full path to the Local Directory and use it as a Source Folder in the Thunderbird to outlook Transfer utility.

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Optimize Thunderbird mbox files before conversion

When you delete or move messages from one Thunderbird folder to another, the source Thunderbird mbox files remain unchanged as the original message is simply marked as deleted or moved and becomes hidden from view. In order to correct the message indexing and optimize space occupied by the mailbox files we recommend to “compact” the Thunderbird folders before you start the conversion.

  • To compact a single folder, right-click on the Thunderbird folder name and select Compact.
  • To compact all folders, select menu File > Compact Folders.

Thunderbird menu Compact

Compaction progress will be shown in the status bar. Wait for the end of compaction and go to the next step.

Thunderbird - Compaction progress

Important! Exit Thunderbird email client prior to running the Thunderbird to Outlook conversion procedure. Thunderbird may block one of the mailboxes data files and this will cause the error during conversion.

Check your Outlook Version (skip this if you know what Outlook edition you have)

Open your Outlook software, click on file > Select Office account and click “About Outlook”. This will help you find out the version.

Outlook version info

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Method 2: How to Export Thunderbird emails to Outlook using the drag and drop method

This method is a poor man’s way to convert thunderbird emails to Outlook with minimum hassle. It can be used if migration from Thunderbird to Outlook does not involve a lot of emails and/or folders.

Step 1: Open your Mozilla Thunderbird software

To export thunderbird to outlook emails, open your Mozilla Thunderbird software. Click on the messages folder you want to migrate.

Step 2: Select the messages to export

In the folder, choose all the messages that you want to export. Right-click on the selected messages and choose the “Save as” option from the menu.

Thunderbird EML save as

Step 3: Choose a destination Folder

A dialog box will appear and you will need to choose a destination folder to save your email files. It is advisable to create a new folder on your desktop to export thunderbird emails into files of EML format. Rename it and then click “Select Folder” and it will export the messages.

Step 4: Import your emails to Outlook

Now you can import Thunderbird profile to Outlook. Drag and drop all the EML files from the new folder to a mailbox folder in Microsoft Outlook. If you drag and drop the folders, the content will remain as it was.

Conclusion on converting Thunderbird to MS Outlook with EML drag-n-drop

While seemingly simple, this method of Thunderbird conversion to Outlook does not necessarily produces the best results. Also, manual drag-n-dropping EML files is tedious and time-consuming. Imagine doing that for hundreds of your folders? Definitely not the best way to spend your time. Especially, if you need to switch from Thunderbird to Outlook fast.

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Method 3: Using Gmail IMAP as a proxy

This method is based on two-steps transferring from Thunderbird to Outlook via a Gmail account. The semi-automated method first uploads emails from Mozilla Thunderbird to Gmail via the IMAP protocol, and then it imports the data to the Outlook mailbox. Here is how to transfer Thunderbird emails to Outlook, step by step.

Step 1: Enable IMAP access in Gmail account

First of all, make sure the IMAP access is enabled in Gmail and if not, enable it.

    1. Sign in to your Gmail account. If you have several – any one will do.
    2. Open the Settings dialog, and switch to “Forwarding and POP/IMAP” tab.
    3. Scroll down to find the “IMAP access” option. Enable it.

Gmail enable IMAP

This will allow third-party email clients like Thunderbird to access Gmail mailboxes via the IMAP protocol.

Don’t forget to save changes.

Step 2: Use Gmail IMAP data to sign in using Thunderbird

Now, we need to setup an account in Mozilla Thunderbird to access Gmail via the IMAP. Let’s do this.

  1. Run Thunderbird. Select any mailbox. It doesn’t really matter, which one, you do this to see the actions screen.
    Thunderbird - new email account
  2. Under “Set Up Another Account” select “Email” to create a new email account. Alternatively, you can use the “File > New > Existing Mail Account” menu for this.
    Thunderbird Existing Account
  3. In the new email account dialog, specify your Gmail IMAP data: username and password.
    Thunderbird - Setup Existing email address
  4. Click the “Continue” button, and select “IMAP” on the next page. Then click Done. This should automatically configure Thunderbird to add a new mailbox linked to the Gmail IMAP box.

What if something goes wrong here? If you see an error message during the setup, you may try to disable the 2-step authentication in Gmail since it can prevent connection of Thunderbird to Gmail. In this case, you need to log in to your Google account, switch to the security settings and disable 2-step authentication option there. Then, open the Less Secure Apps settings in the account, and switch it off. This should resolve the setup problem, so try again this step all over.

Step 3: Copy Thunderbird Mails to Gmail Folder

After you successfully set up a new account in Thunderbird, you can use it to move emails from Thunderbird to Outlook.

Create a new folder under your newly configured Thunderbird account. Then, copy emails from the folder in you Thunderbird account (the one you want to migrate to Outlook) to this Gmail folder.

Thunderbird new folder

Note: this action will automatically start uploading emails to Gmail via the IMAP protocol. Depending on the amount of emails, the process can take a while.

Now, your Thunderbird emails are available from Gmail as well, but we need to migrate from Thunderbird to Outlook, right? So there are a few more steps to do.

You may also want to know how to import messages from Thunderbird to Gmail account.

Step 4: Sign In to Outlook using the same Gmail account (IMAP)

Now everything is ready to start Mozilla Thunderbird to Outlook conversion using Gmail as a proxy.

Run Outlook (both Windows and Mac versions are fine). Sign in to your mail account as usual. Then, sign in using the Gmail account user/password IMAP settings. Sure enough, you should use the same Gmail mailbox as the one you previously added to Thunderbird. Read detailed instruction on how to add Gmail account to Outlook.

Step 5: Synchronization of Thunderbird emails with Outlook via Gmail proxy

Upon startup, Outlook begins synchronization of mailboxes with servers via IMAP, including the new Gmail mailbox. And this is exactly what we want! Let Outlook do its job and allow it to retrieve all Thunderbird-exported emails from your Gmail account. Again, the process can take a while, so be patient.

When it’s done, copy the email data to another Outlook account so you won’t need Gmail IMAP anymore to access them. When the copying finishes, the Gmail account is not needed anymore, so you can disconnect from it.

In principle, you are done already. Export Thunderbird to Outlook is finished. However, you may want to run Thunderbird export to Outlook Data File instead. If that was the case, you can continue from now on.

Step 6: Use Outlook Import/Export Wizard to save emails from Thunderbird to PST

The Outlook’s Import/Export Wizard offers you a convenient shortcut if you want to convert Thunderbird to Outlook PST. In this case, instead of copying mailbox data to Outlook, you can export the Gmail folder fetched via IMAP directly to PST.

    1. First, open Outlook. Use the “File > Open & Export > Import/Export” menu.
    2. Choose the “Export to a File” option in the Wizard and click Next.
    3. Select “Outlook data file’ exporting option.
    4. Click Next again and select the Gmail folder you just synced (see Step 5). Make sure to “Include subfolders” and click Next.
    5. Select where you want to save the resulting PST file and finish the Wizard.

This way you can move Thunderbird to an Outlook PST file.

Conclusion on this method to export Thunderbird to Outlook

As you see, this two-step conversion is moderately simple and is mostly automatic. However, the conversion is in fact done twice, and that creates some ground for various conversion errors. More often than not, the converted emails may appear not in the same format as they were before conversion. Also, Thunderbird may refuse to connect to Gmail via IMAP for a number of reasons, so you may need to try other methods reviewed below in this article in order to successfully convert Thunderbird files to Outlook.

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Frequently Asked Questions

Can I export from Mozilla Thunderbird to Outlook?

Yes. In this article we have presented three working and tested methods of how to export Thunderbird emails to Outlook.

How to how to import Thunderbird mails into Outlook PST?

You can use our Thunderbird to Outlook Transfer automatic tool to automatically retrieve Thunderbird messages from this email client and save them into a PST file that you can open in Outlook.

Can Thunderbird export mbox files to PST?

There is no direct way to export Thunderbird to PST. Mozilla does not offer such an option, so you will need to find a workaround. There are manual methods to export emails to Outlook PST files, but we recommend using our Thunderbird to Outlook converter.

Where are Thunderbird data files stored?

By default, Thunderbird mbox files are located in a profile folder:

C:\Documents and Settings\%USERPROFILE%\Application Data\Thunderbird\Profiles\XXXXXXXX.default\Mail\


C:\Users\%USERPROFILE%\AppData\Roaming\Thunderbird\Profiles\XXXXXXX.default-release\Mail\Local Folders\

Where %USERPROFILE% is your username, and XXXXXXXX is a sequence of arbitrary characters.

In what format does Thunderbird store emails?

Thunderbird stores emails in the mailbox files and corresponding MSF file format which stands for Mail Summary File. This format is not directly compatible with MS Outlook, which is the reason for why so many users often ask how to import Thunderbird mbox files into Outlook. Even though, you cannot export MSF to PST from Thunderbird, you can use our automatic tool for that and avoid many problems with conversion errors, partial importing, wrong or damaged email formatting and other conversion issues.

Are there any limitations in Outlook for the import of Thunderbird emails?

While there are no specific restrictions for Thunderbird messages, it’s not advisable to import emails from the IMAP buffer during synchronization with the IMAP server. Be aware of Outlook’s maximum PST file size limit, as exceeding this limit may interfere with the conversion process. Outlook also has a limit on the size of file attachments it can import, so large attachments in your Thunderbird mailboxes could be a problem. Also, the Outlook MAPI library used to import emails may display an “Out of memory” error. If this happens, try to free up memory by closing other programs. If the problem persists, it may only be resolved by using a computer that has a 64-bit edition of Outlook installed.

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Final Thoughts

Thunderbird to Outlook Transfer software helps move your emails and attachments from one application to another in virtually no time.

If you encounter a problem while converting your emails using our product, please contact our support team with a description of your problem, and we will do our best to get back to you as soon as possible.

Hassle-free email conversion!
Instant solution to convert Thunderbird emails to Outlook PST format and export Thunderbird messages to EML files. Download Thunderbird Converter and start your hassle-free Thunderbird migration now!

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is there a way to transfer the license between computers? as in, deactivate from one and activate on a replacement PC? the PC originally used has actually been replaced and been formatted.

We encourage you to contact our customer support team if you are experiencing any difficulties or have any queries about the software. They are always ready to assist and guide you through any issues you may encounter.

Is there actually a way to transfer address book and and e-mail archive from Thunderbird to Outlook? Thanks.

Sure, start from reading this instruction. If you have any difficulties, please contact us here for assistance.
You may convert Thunderbird address book as well.

I have tried the software repeatedly. HOW DO I enter the activation code?>?>?> I try to enter it and it says to try it first. Starting to think this is a ripoff! I PAID!!! GIVE ME THE COMPLETE VERSION…

According to the EULA terms, you have to ensure that software works properly prior to obtain the activation code. You have to save the result and make sure that the result suits you. This is exactly what is indicated in the message that you have received. Please read the activation instruction.

Hi Gordon
Thanks for the reply but I have resolved my issue.

Looks good, but Ii also need to export an old email account to outlook (I can’t set it up as I have forgotten the password and no longer deal with the original supplier of the email account, although I still get emails for this account)
Can you help please?

Hi, Alan, there is not enough information unfortunately to guess something, please drop us a letter via the contact form, we will try to help you.

After reading this instruction I have only one question now – how to convert also my Thunderbird address book to Outlook contacts?

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How to Export Thunderbird Emails to Outlook

time to read: 16 min