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Open a Gmail MBOX from Google Takeout

When you export Gmail with Google Takeout you get one large .mbox file, usually called “All mail Including Spam and Trash.mbox”. Here is how to make use of it.

Updated 2026-10-26 · 5 min read

What's inside

  • Every message as raw email text, one after another (the MBOX format).
  • Gmail labels in an X-Gmail-Labels header on each message – labels are not folders, so one message can carry several.
  • Spam and Trash, unless you excluded them in Takeout.
  • Attachments embedded in the messages.

Open and search it without importing

Drop the .mbox in Letterlark. It's read in chunks, so archives of many gigabytes work; indexing takes a while. Search by sender, subject, body or attachment name, filter by date, and read messages with their attachments.

Convert it

  • PDF – selected messages, one per page.
  • EML – one file per message in a .zip.
  • CSV – an Excel list of date, sender, recipients, subject and attachments (details).
  • Attachments – everything from the selected messages as one .zip.

Import it into a mail program

Thunderbird (with ImportExportTools NG) and Apple Mail (File › Import Mailboxes) can import MBOX. Gmail itself has no MBOX upload; to put mail back into a Gmail account, import it into Thunderbird and copy it to the Gmail account over IMAP.

Open your mail file now. Letterlark opens PST, OST, MSG, EML and MBOX files in Chrome, Edge, Firefox or Safari on Windows, Mac, Linux or Chromebook. Files are read on your computer – the app page cannot upload anything. Viewing and search are free without limit; exports (PDF, EML, MBOX, CSV, attachments) are free up to 20 messages at a time. A one-time license is $19 (Personal) or $49 (Pro, business use).

Open Letterlark – free

Questions and answers

Can Outlook open an MBOX file?

Not directly. Convert to EML and drag them into Outlook, or import via Thunderbird; results vary by Outlook version.

Why is the Takeout file so big?

It contains every attachment, plus spam and trash unless excluded. Export only selected labels in Takeout to make it smaller.

Sources and product names: Google Takeout help; RFC 4155 (mbox format); Mozilla Thunderbird documentation. Microsoft, Outlook, Gmail, Google Takeout, Apple Mail and Thunderbird are trademarks of their owners. Letterlark is independent and not affiliated with them.