How to Convert .mbox to .eml Files for Microsoft Outlook Using Thunderbird

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When you export emails from Gmail or Google Workspace using Google Takeout, your mailbox is exported as a .mbox file. This format is perfect for archiving, but it can be tricky when you want to open individual emails in applications like Microsoft Outlook or share them one by one.

In this guide, I’ll show you how to convert your .mbox file into individual .eml files, which are compatible with Outlook and other email clients. This process uses Mozilla Thunderbird along with the ImportExportTools NG add-on.

📁 What Are .mbox and .eml Files?

🗃 What is .mbox?

  • .mbox is a Mailbox format that stores all email messages in a single text file, one after another.
  • It is created by Google Takeout and is supported by email clients like Thunderbird, Apple Mail, and others.
  • Outlook does not support the .mbox format natively.

📧 What is .eml?

  • .eml contains a single email per file, including its headers, body, and attachments.
  • It is compatible with Outlook, Thunderbird, and Windows Mail, among other email clients.
  • .eml files are ideal for email backups, forensic review, or sharing individual emails.

🧰 What You’ll Need to Convert .mbox to .eml

  • ✅ Mozilla Thunderbird (free)
  • ✅ ImportExportTools NG add-on
  • ✅ A .mbox file from Google Workspace or Gmail

🔧 Step-by-Step Guide: How to Convert .mbox to .eml Files

📥 Step 1: Install Mozilla Thunderbird

🗂 Step 2: Enable Local Folders in Thunderbird

Thunderbird stores your email files in Local Folders without needing to connect to a mail server.

If you don’t see “Local Folders” in the left pane:

  • Click the ☰ menu → Account Settings
  • Ensure “Local Folders” is listed in the left sidebar.

🔌 Step 3: Install the ImportExportTools NG Add-on

  • Click ☰ → Add-ons and Themes (or press Ctrl + Shift + A)
  • Search for ImportExportTools NG
  • Click “Add to Thunderbird” and restart Thunderbird if prompted.
  • Alternatively, click here to download the add-on directly.

📦 Step 4: Import Your .mbox File into Thunderbird

⚠️ Do not drag the .mbox file directly into Thunderbird. Use the add-on for proper import.

  • Right-click on “Local Folders” and choose: ImportExportTools NG → Import mbox file
  • Select “Import directly one or more mbox files” and browse to find your .mbox file from Google Takeout.

A new folder (e.g., “All Mail”) will appear under Local Folders, containing all the emails from the .mbox file.

💾 Step 5: Export Emails as .eml Files

  • Right-click the folder you imported (under Local Folders)
  • Choose: ImportExportTools NG → Export all messages in the folder → EML format
  • Choose a destination on your local drive for saving the .eml files.

📤 All emails will be exported as individual .eml files, ready for use in Outlook or other email clients.

✅ What’s Next?

  • 🟢 Open the .eml files in Microsoft Outlook by dragging them into any Outlook folder.
  • 🟢 Use the .eml files for documentation, backup, or sharing individual emails.
  • 🟢 Archive them for future reference.

📌 Final Thoughts on Converting .mbox to .eml

Using Thunderbird and the ImportExportTools NG add-on is a quick, easy, and free method to convert .mbox archives into individual .eml files compatible with Microsoft Outlook and other email clients. This method gives you full control over your email data.

If you need a version with screenshots or a downloadable guide, feel free to reach out!

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