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How to Migrate Mac Mail to Thunderbird in Few Easy Steps ?

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Published By Jamie Kaler 
Rollins Duke
Approved By Rollins Duke
Published On April 1st, 2026
Reading Time 6 Min Read

There are multiple free manual & professional approaches to import Apple Mail to Thunderbird with complete data integrity & on my Mac mailboxes:

  • Method 1: Using Built-In Thunderbird Import Tool
  • Method 2: Using Gmail (or any IMAP account) as a bridge
  • Method 3: MBOX Export using ImportExport NG Tools
  • Method 4: With the Mac Mail to Thunderbird Migration Tool

Here we have given step-by-step instructions for each method with pros & cons so you can choose the right method to migrate Apple Mail to Thunderbird based on your technical expertise & needs.

Table of Content Hide

Why Import Apple Mail to Thunderbird?

Both Mac Mail & Mozilla Thunderbird are the predominant email clients used on Mac & Windows devices. Even though Apple Mail offers good features, but still numerous reasons to migrate Mac Mail to Thunderbird, such as:

  • Migrating from a Mac OS environment to Windows or Linux & Thunderbird is a free & open source platform.
  • Take advantage of the add-on feature of Mozilla Thunderbird.
  • To import Apple Mail exported MBOX files in Thunderbird.
  • Thunderbird offers a comprehensive interface for Mail, Contacts & Calendar, while Mac has separate applications for these.
  • Thunderbird has better filter & search settings than Mail.

Important: Migrating Mac Mail to Thunderbird only involves emails with attachments, folder hierarchy, and all other email attributes, as contacts & calendar are stored in separate applications on Mac OS (Apple Calendar & Contacts).

Method 1: Using Thunderbird Only

This method is completely free to use & official method to migrate Apple Mail to Thunderbird within a single device (Mac OS).

  1. Open Mozilla Thunderbird on your Mac.
  2. Click on the Navigation menu (three lines).
  3. Select Tools >> Import.
  4. Choose Apple Mail as the import option & continue.
  5. Select the Apple Mail data to be imported.
  6. Press the Continue & Start Import button to confirm.

Cons of Thunderbird Import Option to Migrate Apple Mail to Thunderbird

  • Extremely slow & often crashes Thunderbird
  • An option is missing in some Thunderbird versions
  • Not useful if you want to restore an Apple Mail backup file in Thunderbird
  • Limited to the same device migration & Mac devices.
  • No selective migration option.

Tip: After you have fully migrated Mac Mail emails to Thunderbird. Ensure you re-add accounts configured in Apple Mail for seamless usage.

Method 2: Using IMAP Bridge to Migrate Mac Mail to Thunderbird

One of the easiest & free solutions to import Apple Mail to Thunderbird is using an IMAP account. It helps you skip the manual hassle of file export and import.

Pre-Requisite: You need an IMAP account that can store the entire Thunderbird profile data in a single account and a stable internet connection. Here we are using a Gmail account as a bridge.

  1. Open Apple Mail on your Mac OS.
  2. Click on Mail >> Add Account.
  3. Select Google & enter your email address & sign in with Google.
  4. Drag & Drop all my Mac email folders and the desired mailbox to your Gmail account.
  5. Open Mozilla Thunderbird.
  6. Click on Menu >> New Account >> Email.
  7. Enter your name & the same Gmail address.
  8. Choose IMAP >> Continue & Sign In with Google.

Cons of IMAP Bridge to Migrate Apple Mail to Thunderbird

  • Limited to 15GB, or you may need to buy additional storage.
  • The process is extremely slow and depends on IMAP sync to get completed.
  • Manual drag & drop is time-consuming and leads to data loss.
  • Does not work offline.

Method 3: ImportExport NG Tools to Export Mac Mail to Thunderbird

This method enables you to import Apple Mail to Thunderbird in a 100% offline way. This offers selective migration of mailboxes with ease.

Note: After testing it is found that it is only helpful for Mac Mail to Thunderbird Export up to 4GB.

Tip: While exporting mailboxes from Apple Mail, place them under a single folder and name them in an identifiable manner for easy import.

  1. Open Mac Mail on your PC.
  2. Right-click the desired Mailbox folder.
  3. Choose Export.
  4. Give a name and choose a saving destination.
  5. Repeat the process for all folders.
  6. Open Thunderbird.
  7. Go to Menu >> Themes & Add-ons.
  8. Install ImportExport NG Tools.
  9. Go to Thunderbird Local Folder.
  10. Right-click & create a new folder (name: AppleMailImport).
  11. Click on the New Folder & choose Import Export NG Tools.
  12. Choose Import MBOX files >> Import MBOX files from Directory.
  13. Select the folder and open.

Wait for the process to get completed, and then Restart Thunderbird.

Cons of ImportExport NG Tools Methods

  • Dependent on a third-party add-on.
  • Loss of folder hierarchy.
  • Not relatives often attachments are lost.

Professional Solution to Migrate Mac Mail to Thunderbird

RecoveryTools Apple Mail Migration Tool is a fast & secure tool that helps you import Mailbox from Apple Mail to Thunderbird without any hassle of add-ons or finding profile folders while ensuring complete data integrity.

Trial Version: Free DEMO edition to check the working & functionality of the Mac Mail to Thunderbird Converter. Also, it allows you to convert 25 items from every folder.

Pros of Using an Automated Tool to Import Apple Mail to Thunderbird

  • No file size or count limitation to migrate Mac Mail to Thunderbird.
  • Auto fetches Thunderbird profile folder location.
  • Ensure complete integrity, including attachments, folder hierarchy, email headers & metadata, and complete formatting.
  • Works 100% offline and is a standalone application.
  • Functional on all Mac & Windows devices and compatible with all Thunderbird versions.
  • Have Filters – Date Range, From, To, Subject, Exclude Folders, Root Folder, Use Client Submit Time to selectively transfer the data.

Follow these 8 Simple Steps to Migrate Mac Mail to Thunderbird

  1. Run RecoveryTools Mac Mail to Thunderbird Migrator on your Windows PC.
  2. Browse Mac mail files by clicking on the Select Files or Select Folders option.
    apple mail to gmail migration process begins
  3. Then, choose all required Mac Mail mailbox items that you want to export to your Gmail account.choose required files
  4. Now choose the Thunderbird option from the given list of saving options.
    select thunderbird saving option
  5. Then, the user has to set up Mac Mail to Thunderbird Migration options, like changing the destination path, etc.
    browse destination
  6. Hit the Convert button, then instantly start the process to import Mac Mail to Thunderbird.
    Migrate Mac Mail to Thunderbird process begins
  7. Finally, once the conversion process is finished, click on the OK button to confirm & exit.
    Migrate Mac Mail to Thunderbird process completed
  8. Run Thunderbird to see the migrated data.
    run thunderbird

Wrapping Up

At the present time, migration from one account to another is not a simple and easy task. During the migration of Mac Mail to Thunderbird, users have experienced numerous challenges. In the above section, we have discussed a manual process, but it is also very complex and time-consuming. To overcome these constraints, a user is suggested to use an alternate solution, i.e., Mac Mail to Thunderbird Migrator. It is the one-stop solution that can easily import Mac Mail to Thunderbird efficiently and reliably. Henceforth, some advantages of the software are also covered in the above section.