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MSG to MBOX Converter

Combine Outlook MSG files into one MBOX mailbox for import into Thunderbird, Apple Mail or other clients.

Your files never leave your device

How to convert MSG to MBOX

  1. 1

    Choose your MSG files

    Click the upload area or drag files onto it. Nothing is uploaded — files are opened locally.

  2. 2

    Start the conversion

    Press the convert button. Your browser converts the files in seconds.

  3. 3

    Download the result

    Download one file with everything combined, ready to save or print.

Merge many individual messages from Microsoft Outlook into a single MBOX file — the easiest way to import a batch of emails into Thunderbird or Apple Mail, or to archive them as one file.

Read the full guide with screenshots

What is MSG?

MSG is Microsoft Outlook’s single-message format. Dragging an email out of Outlook on Windows creates one. It can’t be opened on a Mac, phone or in webmail without conversion.

What is MBOX?

MBOX stores a whole mailbox — thousands of emails — in one file. Google Takeout, Thunderbird and Apple Mail exports all use it.

Is it private?

Yes. Unlike upload-based converters, ZapMorph processes files inside your browser tab, so the file stays on your device. It is never transmitted, stored or logged — close the tab and it’s gone.

Frequently asked questions

Is the msg to mbox converter free?

Yes. Convert 1 file a day without an account, or 5 files a day with a free account. Pro removes all daily limits.

Are my files uploaded to a server?

No. The conversion runs entirely in your browser, so your files never leave your device. We only count how many files you convert — never their names or contents.

What is the maximum file size?

Up to 25 MB per file without an account, 50 MB with a free account, and 1 GB on Pro. Very large files also depend on your device’s memory.

Can I convert multiple MSG files at once?

Yes. Add several files and they’re combined into one document in the order you choose — 5 files on the free plan, 50 on Pro.

Does it work on Mac, Windows, iPhone and Android?

Yes. It works in any modern browser — Chrome, Edge, Firefox and Safari — on desktop and mobile, with nothing to install.

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MSG to PDF

MSGPDF

Convert Outlook MSG files to PDF with sender, recipients, date and message body. Private — nothing is uploaded.

MSG to HTML

MSGHTML

Convert Outlook MSG files to HTML pages that open in any browser, with headers and formatting kept.

MSG to Text

MSGText

Extract plain text — headers and body — from Outlook MSG files. Ideal for search, archiving and AI tools.

MSG to JSON

MSGJSON

Convert Outlook MSG files to structured JSON: headers, recipients, body and attachment details.

MSG to CSV

MSGCSV

Export Outlook MSG files to a CSV spreadsheet — one row per email with date, sender, subject and body.