If you need to save Thunderbird messages outside the email client, there are several ways to export emails from Thunderbird. The right method depends on whether you want individual emails, an entire mailbox, a backup, or a different file format such as EML, PDF, HTML, or PST.
Thunderbird can save individual messages directly, while additional tools can provide more options for bulk Thunderbird email export. If your Thunderbird mailbox is stored in MBOX format and you need to convert it into another format, an MBOX conversion tool can also be considered.
Why Export Emails from Thunderbird?
Exporting Thunderbird emails can be useful in several situations:
Email backup: Keep an additional copy of important messages outside Thunderbird.
Migration: Move emails from Thunderbird to another email application.
Archiving: Store old messages separately without relying on the active mailbox.
File sharing: Save selected emails in formats that are easier to share.
Data preservation: Keep important correspondence accessible even if the original Thunderbird profile becomes unavailable.
Format conversion: Convert MBOX-based Thunderbird data into formats required by other applications.
Thunderbird itself provides some basic saving options, while additional utilities can provide broader export and conversion choices. Mozilla Support discussions also describe saving selected messages as EML and using ImportExportTools NG for additional export options such as HTML and text.
Method 1: Export Thunderbird Emails as EML
EML is one of the most useful formats when you want to preserve individual emails.
Step 1: Open Thunderbird
Launch Mozilla Thunderbird and open the mailbox containing the messages you want to export.
Step 2: Select the Emails
Select one or more emails from the required folder. You can use Ctrl+A when you want to select all messages in the folder.
Step 3: Save the Messages
Use Thunderbird's Save As option and choose a suitable location. Thunderbird can save selected messages as EML files.
Step 4: Verify the Exported Files
Open the destination folder and check whether the EML files were created successfully. Open a few files to confirm that the message content and attachments are available as expected.
Method 2: Export Thunderbird Mailboxes as MBOX
If your objective is to preserve a complete mailbox rather than individual emails, MBOX can be a suitable choice.
Thunderbird stores mail in mailbox files, and MBOX is commonly used for email archiving and migration. An export/import extension such as ImportExportTools NG can provide options for exporting and importing MBOX files. Mozilla Support discussions also document using the extension to export Thunderbird folders as MBOX.
Basic Process
Open Thunderbird.
Identify the folder containing the emails.
Select the appropriate export option.
Choose MBOX as the output where available.
Select a destination folder.
Verify the resulting mailbox file.
Keep a backup of the original Thunderbird profile before making major changes to mailbox files.
Method 3: Export Thunderbird Emails to HTML or TXT
HTML and TXT can be useful when the primary goal is reading or reviewing email content rather than importing it into another email client.
For example:
HTML is useful when you want to retain a web-style representation of the message.
TXT is useful when you only need readable plain-text content.
Thunderbird Support discussions describe additional export options through ImportExportTools NG, including HTML and plain-text exports.
The exact options available can depend on the Thunderbird version and the extension being used.
Method 4: Export Thunderbird Emails to PDF
PDF is useful when emails need to be shared, archived as documents, or reviewed without opening an email client.
For a small number of messages, you can use Thunderbird's printing functionality and select a PDF printer or Save to PDF option where available.
However, this approach is less convenient when you have hundreds or thousands of emails because each message may require additional handling.
If the requirement is specifically to convert an MBOX mailbox into PDF in bulk, a dedicated MBOX conversion utility may be more practical.
Method 5: Export Thunderbird Emails to Outlook PST
If you are moving from Thunderbird to Outlook, simply saving emails as EML may not be enough. Outlook commonly works with PST for mailbox data, so a conversion step may be required.
One approach is to first preserve Thunderbird data in MBOX and then convert the MBOX file into PST.
If you have Thunderbird MBOX files and need to convert them into another format, SysTools MBOX Converter is one option to evaluate. According to its current product documentation, it supports Thunderbird MBOX data and provides export options including PST, EML, MSG, NSF, PDF, HTML, CSV, MHT, and TXT. It also supports adding individual MBOX files or folders containing multiple MBOX files.
A typical workflow is:
Locate the Thunderbird MBOX file.
Open the MBOX Converter.
Add the MBOX file or folder.
Preview the available email data.
Select the required output format.
Choose the destination location.
Start the conversion.
Open the resulting file and verify the emails.
This approach is particularly relevant when export Thunderbird emails to different formats is required rather than simply saving a few individual messages.
You have an old Thunderbird MBOX backup.
You want to inspect emails before conversion.
You need to identify a particular mailbox or message.
You want to verify the contents of an archived MBOX file.
The viewer and converter serve different purposes: a viewer is primarily useful for opening and inspecting MBOX data, whereas a converter is intended for changing MBOX data into another file format.
Common Problems When Exporting Thunderbird Emails
Exporting the Wrong Mailbox
Thunderbird may contain multiple accounts and folders. Always check the selected folder before starting an export.
Not Backing Up the Original Data
Never treat the exported copy as your only backup. Keep the original Thunderbird profile or MBOX files until the exported data has been verified.
Losing Folder Organization
Some export methods save individual messages without reproducing the complete Thunderbird folder hierarchy. If folder organization is important, check the output structure carefully.
Choosing an Unsuitable Format
An email format designed for another application may not be the best choice for simple archival. Select the output based on how you intend to use the exported data.
Exporting a Large Mailbox at Once
Large MBOX files can contain thousands of messages and attachments. For large-scale exports, check available disk space and consider processing data in manageable groups.
Best Practices for Thunderbird Email Export
Follow these practices before and after exporting:
Create a backup first.
Identify the exact folders you need.
Choose the output format based on your destination.
Keep the original MBOX files unchanged.
Check attachments after export.
Open a sample of exported emails to verify them.
Use meaningful filenames and folder structures.
For large migrations, test a small batch before processing everything.
What should I do before exporting a large Thunderbird mailbox?
Create a backup of the original Thunderbird profile or MBOX files, check available storage, and test the export with a small group of messages first. This makes it easier to identify formatting, attachment, or folder-structure issues before processing the complete mailbox.
Conclusion
There is no single method that works best for every Thunderbird email export requirement. Saving individual messages as EML is practical for small exports, while MBOX is more appropriate when preserving complete mailbox data. HTML, TXT, and PDF can be useful when the emails need to be read or archived as documents.
If the requirement is to export emails from Thunderbird into several different formats, the workflow becomes easier when the Thunderbird MBOX data is first identified and verified. A tool such as SysTools MBOX Viewer can be used to inspect MBOX files, while SysTools MBOX Converter can be considered when the MBOX data needs to be converted into formats such as PST, EML, MSG, PDF, HTML, CSV, MHT, or TXT.
