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How to Enable the Greyed Out MBOX Import Option? – Instant Fix Inside!

Ritu Roy | fix how to mac os MBOX software technology | 6 minutes read | Modified on: 05-07-2025
Fix MBOX import issue

When migrating emails to other clients, users often rely on formats like MBOX, especially when working with Mozilla Thunderbird. MBOX is widely used for storing and transferring emails within Thunderbird. However, some users face a common issue where the “Import MBOX Files” option appears greyed out or disabled in Thunderbird, making it impossible to import mailbox files directly.

Even after installing necessary add-ons like ImportExportTools NG, the import feature may still remain inactive or non-functional. If you’re experiencing this issue, don’t worry, there are simple and effective ways to resolve it without going through complicated steps.

Understanding MBOX Files and Thunderbird

Before diving into the solutions, it’s important to understand what MBOX files are and how Mozilla Thunderbird interacts with them.

MBOX is a widely used file format designed to store a collection of email messages in a single plain text file. Each email entry is appended one after another, typically separated by a line beginning with “From”. Due to its simplicity and broad compatibility, MBOX is supported by many email clients for storing and transferring messages.

Mozilla Thunderbird is a popular, free, and open-source email client developed by Mozilla. It supports the MBOX format natively, allowing users to manage and migrate email data with ease. However, Thunderbird does not offer a built-in option to import MBOX files directly through the default interface.

To enable this functionality, users need to install an add-on, such as ImportExportTools NG, which unlocks the import/export features for MBOX and other email file types.

Recommendation: If the “Import MBOX Files” option is greyed out or not functioning in Thunderbird, even after installing add-ons—the best alternative is to use a reliable MBOX Converter Tool.

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This widely recognized software provides a direct way to import MBOX files into Thunderbird’s default profile folder without requiring any additional extensions or manual configurations. The tool is designed for both beginners and professionals, offering a hassle-free experience with built-in features that handle the entire import process smoothly.

Why is “Import MBOX Files” Greyed Out in Thunderbird?

If you’re encountering the “Import MBOX Files” option greyed out in Thunderbird, you’re not alone. This is a common issue and usually stems from misconfigurations or missing components within the Thunderbird email client.

By default, Mozilla Thunderbird does not include a built-in MBOX import feature. Instead, it relies on third-party extensions, specifically the ImportExportTools NG add-on to enable importing MBOX files. Without this extension, Thunderbird lacks the necessary functionality to process and recognize MBOX file imports.

Even if the add-on is installed, the option may still appear greyed out due to other underlying issues.

Read More – Fix Common MBOX Files Errors

Other Common Reasons for the Issue

Here are a few additional factors that may cause the import option to remain disabled:

Corrupt Thunderbird Profile – A damaged or corrupted Thunderbird user profile can interfere with core functions, including the import/export features. If this is the case, you may need to repair or recreate your Thunderbird profile.

Tip: Search for solutions on how to “fix a corrupt Thunderbird profile.”

Outdated Thunderbird Version – Running an older version of Thunderbird may lead to compatibility issues with newer versions of the ImportExportTools NG add-on. Always ensure that both Thunderbird and the add-on are updated to the latest versions.

Incorrect File Permissions – If the MBOX file has restricted access permissions, Thunderbird might be unable to read or import it, resulting in a non-functional or greyed-out import option.

Tip: Check the file properties and ensure full read/write access is granted.

Unsupported or Misplaced MBOX File – The file you’re trying to import must be a valid, uncorrupted MBOX file, and ideally placed in a proper location (like your local system). Improper formatting or directory structure may also lead to Thunderbird not recognizing the file.

How to Use the Add-on and Perform the Import Process in Thunderbird

If you’re facing the “Import MBOX files” greyed-out issue in Thunderbird, the solution is often simple: install and properly configure the ImportExportTools NG add-on. This add-on unlocks the ability to import MBOX files directly into Thunderbird folders.

Step 1: Install the “ImportExportTools NG” Add-on

  1. Launch Thunderbird on your system.
  2. Navigate to Tools > Add-ons and Themes.
  3. In the Add-on Manager, search for “ImportExportTools NG”.
  4. Click “Add to Thunderbird” and then hit “Add” to confirm installation.
  5. If prompted, restart Thunderbird to complete the setup.

Step 2: Use the Add-on to Import MBOX Files

Once the add-on is installed and Thunderbird has restarted, follow these steps:

  1. Go to the folder where you want to import the MBOX emails.
  2. Right-click the folder and choose ImportExportTools NG from the context menu.
  3. Select “Import MBOX file” from the list of options.
  4. Choose one of the following import methods:
    • Import directly one or more MBOX files
    • Import MBOX files from a directory
  5. Browse and select your MBOX file(s), then click Open.
  6. Thunderbird will begin importing the selected emails.
  7. Once the import is complete, review the messages in the folder to ensure everything is intact.

Tip: If the “Import MBOX files” option is still greyed out after installation, proceed to the troubleshooting steps below.

Fix: “Import MBOX Files” Greyed Out in Thunderbird

If the import option remains greyed out even after installing the add-on, try these fixes:

1. Restart Thunderbird

Sometimes, the add-on needs a proper restart to activate. Close Thunderbird completely and reopen it.

2. Check and Reinstall the Add-on

  • Open Tools > Add-ons and Themes.
  • Find ImportExportTools NG in the list.
  • If enabled but still not working, click Remove.
  • Reinstall the add-on using the same steps as above.
  • Restart Thunderbird.

3. Update Thunderbird

An outdated version may not fully support the latest add-ons.

  • Go to Help > About Thunderbird.
  • Thunderbird will check for updates automatically.
  • If available, install the update and restart the application.

4. Check Thunderbird Profile

Corrupted profiles can disable certain features, including import options.

Back Up Your Profile First:

  • Navigate to Help > More Troubleshooting Information > Open Folder.
  • Copy and save the profile folder as a backup.

Create a New Profile:

  1. Press Windows + R, type thunderbird.exe -P, and press Enter.
  2. Click Create Profile, name it, and set it as the default.
  3. Launch Thunderbird with the new profile.
  4. Install ImportExportTools NG and check if the import option works.

Optional: If successful, migrate your data from the old profile to the new one.

Frequently Asked Questions (FAQs)

Q1: Why is the “Import MBOX File” option not showing in my Thunderbird?
A: The “Import MBOX File” option only appears when the ImportExportTools NG add-on is installed and enabled. Thunderbird does not have a built-in feature for importing MBOX files by default.

Q2: Is “ImportExportTools NG” safe to use?
A: Yes, it is completely safe. ImportExportTools NG is a widely trusted add-on available from the official Thunderbird add-ons repository.

Q3: How do I use the “ImportExportTools NG” add-on?
A: You can install the add-on via Thunderbird’s Add-ons Manager. Once installed and enabled, all import and export options for MBOX files will be accessible within Thunderbird.

Conclusion

Importing MBOX files into Thunderbird can sometimes be challenging, especially when the “Import MBOX Files” option is greyed out or disabled. This issue usually arises due to missing add-ons, outdated software, or profile-related problems.

In this guide, we covered how to properly install and use the ImportExportTools NG add-on to enable MBOX imports. We also discussed common reasons why the option might not work and shared practical troubleshooting steps.

By following these instructions, you can smoothly import your MBOX files into Thunderbird without hassle. If problems persist, professional MBOX File Converter tool offer a reliable alternative for seamless mailbox migration.