How do I import email from a Proton backup .eml file into Thundermail?

If you are migrating to Thundermail from Proton (or any other email provider that allows you to export your messages as .eml files), the Thunderbird desktop client makes the transition seamless.

This guide will walk you through exporting your messages from your old provider and importing them into Thunderbird using a powerful community add-on.

Before you begin, ensure you have the following:

1. The Thunderbird Desktop client installed on your computer.
2. A folder on your computer containing your messages in .eml format (exported from your previous provider).
3. The ImportExportTools NG Add-on. This is a free, open-source tool that extends Thunderbird's import capabilities.

Firstly, are you a paid Proton subscriber?

• As an alternative to exporting your mail manually, paid Proton subscribers can simply import messages directly into Thunderbird using the Proton Mail Bridge.
• If you are not a paid Proton subscriber, please continue with the instructions below.

Export your messages from your old provider

1. Use the Proton Mail Export Tool to download your messages.
2. Important: Save these files into a dedicated folder on your computer (such as a new Desktop folder named Email_Migration_Backup). Ensure your messages are saved as .eml files.

Install the ImportExportTools NG Add-on

Thunderbird comes with many built-in features, but forbulk mail migrations, we recommend the ImportExportToolsNG Add-on.

1. Open Thunderbird.
2. Click the menu (≡) button, then select Add-ons and Themes.
3. In the "Find more add-ons" search bar near the top, type ImportExportTools NG and press Enter.
4. Click the "+ Add to Thunderbird" button next to ImportExportTools NG.
5. Follow the prompts to complete the installation. Note: You may be asked to restart Thunderbird to activate the extension.

Import your messages into Thunderbird

Once your .eml files are saved on your computer and your Add-on is installed, follow these steps to bring your messages into Thunderbird:

• Open Thunderbird and navigate to the email account where you want your messages to live.
• Create a new folder (optional, but recommended):
  1. Right-click on your email address in the left-hand column.
  2. Select "New Folder..." and name it something like Migrated from Proton. This keeps your existing emails organized and separate from your new incoming mail.
• Start the import:
  1. Right-click on the folder you just created.
  2. Hover over "ImportExportTools NG" in the menu.
  3. Select "Import EML messages..."
• Select your files - a window will appear asking how you want to import. You can import individual messages (Individual Email Messages) or all of the messages in your export (All EML Messages from a Directory and Subdirectories)
• Locate your files and begin importing:
  1. Navigate to the computer folder where you saved your exported messages.
  2. Click "Open" on the folder to begin the process, or select only individual messages if that is what you prefer.

Thunderbird will now process the files. Once finished, your messages will appear in the mail folder you selected. You can now browse, search, and manage your historical emails right alongside your new messages!

Pro tips for a smooth migration

• Migrate in batches. If you have thousands of emails, try importing them in smaller batches (such as 500 at a time) to prevent Thunderbird from slowing down or freezing during the process.
• Check your mail folder. After the import, take a moment to verify that the "Date" and "Sender" information from your messages are correct.
• Keep your backup. Do not delete your original .eml folder until you have verified that all messages have successfully appeared in Thunderbird and everything is working normally. Or, just keep the backup safe for as long as you'd like, just in case!
• Still need help? If you encounter any issues during the Thunderbird side of your migration, please contact the Thundermail support team.

Thanks to the Thunderbird desktop client and its incredible community of Add-on developers, you're now ready to import your existing mail from providers like Proton into your shiny new Thundermail account!