MSG File Viewer
Open Outlook .msg email files without Outlook. See the sender, recipients, date, formatted body, internet headers and every attachment, convert the message to .eml, and save attachments one by one or as a ZIP. Everything is read locally in your browser.
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| Tag | Property | Type | Value |
|---|
How to use the MSG File Viewer
- Open a .msg file: drag it onto the drop zone or press Choose MSG file. A sample message is loaded so you can see how it works first.
- Read the message: the header card shows the sender, recipients and date; the Message tab shows the formatted body.
- Check the attachments: open the Attachments tab to download files, preview images or open an attached email.
- Inspect technical details: the Headers tab shows the internet headers and Properties lists every stored MAPI property.
- Convert or save: press Download as .eml to get a standard email file, or download the body as HTML or text.
What is stored inside an Outlook .msg file
A .msg file is a small file system of its own: a Compound File Binary (CFB) container with storages (folders) and streams (files). Outlook writes each property of the message as a stream named __substg1.0_ followed by an eight-digit hexadecimal property tag, keeps fixed-size values in a __properties_version1.0 stream, and puts every recipient and attachment in its own storage. This viewer reads that structure directly, which is why it does not need Outlook.
| Property tag | Name | What it holds |
|---|---|---|
0x0037 | Subject | The subject line, including prefixes such as RE: or FW: |
0x0C1A / 0x5D01 | SenderName / SenderSmtpAddress | Who sent it; internal Exchange senders may only have an X.500 address in 0x0C1F |
0x0E04, 0x0E03, 0x0E02 | DisplayTo, DisplayCc, DisplayBcc | Recipient display names as one string; full addresses are in each __recip_version1.0_# storage |
0x0039 / 0x0E06 | ClientSubmitTime / MessageDeliveryTime | When the message was sent and when it arrived (UTC FILETIME values) |
0x1000 | Body | Plain-text version of the message |
0x1013 | BodyHtml | HTML version of the message, when Outlook stored one |
0x1009 | RtfCompressed | Rich text body compressed with the LZFu algorithm; often wraps the original HTML |
0x007D | TransportMessageHeaders | The original internet headers (Received, DKIM, SPF results) for mail from outside |
0x3701 | AttachDataBinary / Object | Attachment contents, or a nested message storage for attached emails |
0x3712 | AttachContentId | The cid: name that HTML bodies use to show inline images |
Tips for working with .msg files
- Sharing with Mac or Gmail users: convert the message to .eml first. Apple Mail and Thunderbird open .eml directly, and you can forward its attachments normally.
- Checking a suspicious email: leave remote images blocked, look at the real sender address next to the display name, and copy the headers into an email header analyzer to check SPF, DKIM and the Received path.
- Legal and e-discovery exports: the Properties tab and its CSV export show the exact sent and delivery timestamps and the Internet Message-ID, which are useful for documenting a message.
- Forwarded emails as attachments: an email attached to another email is stored inside the .msg. Use Open message in the Attachments tab to read it, and the breadcrumb to go back.
- Dates: Outlook stores times in UTC. The viewer shows them in your device's time zone and in ISO 8601 UTC form.
Frequently asked questions
What is a .msg file?
A .msg file is a single Outlook item (usually an email) saved by Microsoft Outlook when you drag a message out of the mailbox or choose Save As. It uses Microsoft's Compound File Binary format (the same container as old .doc and .xls files) and stores the message as MAPI properties: subject, sender, recipients, bodies, attachments and more.
How do I open a .msg file without Outlook?
Drop it into this viewer. It parses the file directly in your browser, so it works on Windows, Mac, Linux, Chromebooks and phones without Outlook or any add-in. You can then read it, save the attachments or convert it to .eml, which Apple Mail, Thunderbird and most email apps open natively.
Is my email uploaded anywhere?
No. The file is read with JavaScript on your device and never sent to a server. Remote images in the message body are also blocked by default, because they can act as tracking pixels that tell the sender when and where the email was opened.
Why can't I see the internet headers?
Outlook saves the original internet headers (PR_TRANSPORT_MESSAGE_HEADERS) only for messages received from outside the organization. Drafts, sent items and mail delivered inside the same Exchange or Microsoft 365 tenant usually have none, so the Headers tab will be empty for them.
What is the difference between .msg and .eml?
.msg is Outlook's proprietary binary format, while .eml is a plain-text MIME message (RFC 5322) that almost every email program understands. Converting to .eml keeps the sender, recipients, date, plain and HTML bodies and attachments, but Outlook-only data such as categories, flags or follow-up reminders is not carried over.
Can it open encrypted or signed messages?
Messages signed with S/MIME open normally, but the signature is not verified. Messages encrypted with S/MIME or Microsoft Purview / IRM protection store their content in an encrypted attachment that can only be decrypted with the recipient's private key in Outlook, so this viewer can show the envelope (sender, subject) but not the body.
What is a .oft file?
An .oft file is an Outlook template. It has the same internal format as .msg, so this viewer can open it to show the template's subject, body and attachments.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.