How to open a Google Takeout Gmail backup on Windows

Google recommends viewing Takeout exports on a desktop computer. The included archive_browser.html describes the formats in that particular export. Gmail messages, headers, and attachments are stored in MBOX; Gmail labels are preserved in a special header that mail clients do not interpret uniformly.

Open the archive in this order

1. Preserve the original download.
   Make a working copy before extracting it. If Google split the export into several ZIP files, download and extract every part into the same working area.
2. Read Google’s archive guide.
   Open archive_browser.html, then browse to Takeout\Mail. The Gmail archive normally ends in .mbox.
3. Install Thunderbird and the MBOX add-on.
   In Thunderbird, open Add-ons and Themes and install ImportExportTools NG from the official Thunderbird Add-ons catalog. This is a third-party extension; the built-in Import Tool documentation does not promise direct raw-MBOX import.
4. Import into Local Folders.
   Create a new folder under Local Folders. Right-click it, choose ImportExportTools NG → Import mbox file → Individual mbox files, then select the extracted .mbox file.
5. Verify before deleting anything.
   Open messages from several dates and check attachments. Keep the original archive until you have confirmed the imported copy is complete.

If the result looks wrong

Labels do not look like Gmail folders

Google stores labels in the X-Gmail-Labels header and notes that mail clients do not interpret it uniformly. Missing folder structure does not necessarily mean missing messages.

The import takes a long time

A large MBOX is one long mailbox file. Let the import finish and avoid moving the source file during processing. If the add-on reports an error, record the Thunderbird and add-on versions before seeking help.

Recent messages are missing

Google warns that changes made between requesting the export and creation of the archive may not be included. Create a newer export if those messages matter.

Sources and limits

• Google Account Help — download and open exported data, checked 13 Aug 2026.
• Gmail Help — export Gmail data, checked 13 Aug 2026.
• Thunderbird Help — built-in Import Tool, checked 13 Aug 2026.
• Thunderbird Add-ons — ImportExportTools NG listing, checked 13 Aug 2026.
• Mozilla Support — current MBOX import menu path, community guidance checked 13 Aug 2026.

This guide is based on current public documentation and support guidance. We did not run your archive or claim a hands-on test of your Thunderbird installation.