How can I open MSG files without Microsoft Outlook?

Download Univik MSG Viewer (free), install it on Windows, and double-click any MSG file or drag files into the application. MSG Viewer reads the proprietary Outlook format directly without needing Outlook installed, displaying emails with full formatting and attachments.

What is an MSG file and why does it need special software?

MSG is Microsoft's proprietary email format used exclusively by Outlook. Unlike standard EML files, MSG uses a binary Compound File format that most applications cannot read. MSG files contain Outlook-specific features like categories, flags, voting buttons, and rich formatting that require specialized software to decode.

Can MSG Viewer open MSG files received as email attachments?

Yes! When someone using Outlook forwards you an email as an attachment, it arrives as an MSG file. MSG Viewer opens these attachments directly without importing them into any email client, even if you don't have Outlook installed.

Does MSG Viewer support nested MSG files (emails within emails)?

Yes! MSG Viewer fully supports nested MSG files - emails that contain other MSG files as attachments. You can view the parent email and open any embedded MSG attachments directly within the viewer, navigating through multiple levels of forwarded emails.

Can I view Outlook categories, flags, and voting options in MSG files?

Yes! Unlike basic MSG readers, Univik MSG Viewer displays Outlook-specific properties including color categories, follow-up flags, importance levels, sensitivity settings, and voting button responses that are embedded in the MSG file.

Microsoft Outlook Format — No Outlook License Required

Univik MSG File Viewer
Open Outlook Emails Without Outlook

View Microsoft Outlook .msg files without Outlook installation. Access emails, attachments, categories, flags, and all Outlook-specific properties — completely free.

Download Free MSG Viewer

Version 6.1 | 14 MB | Windows 7/8/10/11 | No Outlook needed

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Outlook Properties

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The Problem

Why MSG Files Are Hard to Open

MSG is Microsoft's proprietary format. Here's why you need a specialized viewer.

❌ No Outlook Installed

You received an MSG file but don't have Microsoft Outlook. Without a $150+/year Microsoft 365 subscription, you can't open it.

✓ Solution: MSG Viewer opens MSG files without any Outlook license.

❌ Proprietary Binary Format

Unlike EML files, MSG uses a binary "Compound File" format. You can't view it in Notepad or standard email clients like Thunderbird.

✓ Solution: MSG Viewer decodes the binary format and displays readable content.

❌ Outlook-Specific Features

MSG files contain categories, flags, voting buttons, and RTF formatting that basic viewers miss entirely.

✓ Solution: MSG Viewer preserves all Outlook properties and metadata.

❌ Nested MSG Attachments

Forwarded emails arrive as MSG files inside MSG files. Extracting and viewing these nested emails is complicated.

✓ Solution: MSG Viewer handles nested MSG files seamlessly.

❌ RTF and HTML Content

Outlook stores email body in RTF, HTML, or both. Non-Outlook software often shows garbled or plain text only.

✓ Solution: MSG Viewer renders RTF and HTML with full formatting.

❌ Quick Review Without Import

Even with Outlook, you'd need to import MSG files into your mailbox just to read them — cluttering your inbox.

✓ Solution: MSG Viewer opens files directly without importing anywhere.

Univik MSG Viewer is a free Windows application that opens and displays Microsoft Outlook .msg email files without requiring Outlook to be installed. It reads the proprietary binary format and presents emails with full formatting.

What is an MSG file? MSG is Microsoft's proprietary email format used exclusively by Outlook. Unlike standard EML files (plain text), MSG files use a binary "Compound File" structure (similar to .doc files) that stores email content, attachments, and Outlook-specific properties like categories, flags, and voting buttons.

Common scenarios: Receiving MSG email attachments from Outlook users, viewing archived Outlook emails without an Outlook license, reviewing legal evidence or compliance documents in MSG format, opening MSG files on computers without Microsoft 365 subscription.

Technical details: Parses OLE Compound Document format, supports Unicode and ANSI MSG files, handles embedded attachments including nested MSG files, decodes RTF and HTML body content, extracts all MAPI properties.

Key advantage: While Outlook costs $150+/year with Microsoft 365, MSG Viewer is completely free and opens the exact same files with all their Outlook-specific properties preserved.

MSG Viewer Facts

✓ 100% Free
✓ No Outlook Required
✓ Full Outlook Properties
✓ Categories & Flags
✓ Nested MSG Support
✓ RTF/HTML Rendering
✓ Attachment Preview
✓ Windows 7-11

Powerful Features

What MSG Viewer Can Do

Every feature designed for complete MSG file access without Outlook.

Open Without Outlook

View MSG files instantly without Microsoft Outlook or Microsoft 365 subscription. No license, no configuration — just open and read.

Outlook Categories & Flags

View color categories, follow-up flags, importance levels, and sensitivity settings exactly as they appear in Outlook.

Nested MSG Files

Handle emails within emails — when someone forwards an MSG attachment inside another MSG file, open all nested levels seamlessly.

RTF & HTML Rendering

Full rendering of Outlook's RTF and HTML email bodies with formatting, fonts, colors, tables, and inline images preserved.

Attachment Preview

Preview images, PDFs, and Office documents directly. Save individual attachments or extract all attachments in batch.

Voting Responses

View voting button options and responses stored in MSG files — a feature unique to Outlook that most viewers ignore.

MAPI Properties

Access all underlying MAPI properties — transport headers, recipient details, delivery timestamps, and internal Outlook metadata.

Search & Filter

Load multiple MSG files and search across all of them by sender, recipient, subject, date, or content keywords.

Read-Only Safety

MSG Viewer never modifies original files — perfect for legal evidence, compliance reviews, and forensic examination.

Quick Start Guide

How to Open MSG Files

View Outlook emails in under 2 minutes — no Outlook required.

Step 1: Download MSG Viewer

Get the free installer — only 14 MB download.

Download MSG Viewer →

Step 2: Install and Launch

Run the installer and follow the wizard. Installation takes less than a minute. Launch MSG Viewer when complete.

Step 3: Open MSG Files

Double-click any MSG file to open it directly, or use "Add Files" to select multiple MSG files. You can also drag and drop files into the window.

Step 4: View Complete Email

Browse the email with full Outlook formatting. View categories and flags, preview attachments, check headers, open nested MSG files, and print if needed.

💡 Pro tip: Set MSG Viewer as your default application for .msg files. Then you can double-click any MSG file to open it instantly — even without Outlook installed!

Understanding the Format

What is an MSG File?

The proprietary email format that only Outlook truly understands.

MSG = Outlook Message Format

An MSG file is Microsoft Outlook's proprietary format for storing individual email messages. When you save an email from Outlook using "Save As," it creates an MSG file containing the complete message — headers, body, attachments, and all Outlook-specific metadata.

Why MSG Files Are Different

Unlike standard email formats (EML), MSG files use a binary structure called OLE Compound Document — the same technology used in .doc files. This format is based on MAPI (Messaging Application Programming Interface), Microsoft's proprietary email API.

This is why opening an MSG file without Outlook is challenging — most applications simply don't understand the binary MAPI property structure inside.

MSG File Facts

📁 Extension: .msg
🏢 Created by: Microsoft Outlook
⚙️ Structure: OLE Compound Document
🔧 Based on: MAPI Properties
📊 Common in: Corporate, Legal, Government
⚠️ Opens in: Outlook only (without special tools)

Corporate Email Archives

Companies save important emails as MSG files for records retention and compliance.

Legal Evidence

Law firms and courts use MSG files to preserve email evidence with full metadata.

Email Attachments

Outlook users often forward emails as MSG attachments to share complete messages.

Complete Email Access

What's Inside an MSG File?

MSG Viewer displays every component stored in the Outlook message format.

📧

Email Headers

• From: Sender name and email
• To: Primary recipients
• CC: Carbon copy recipients
• BCC: Blind copy (if sender)
• Subject: Email subject line

🕐

Date & Time

• Sent: When email was sent
• Received: When delivered
• Timezone: Original timezone info
• Modified: Last modification date
• Created: File creation timestamp

📝

Message Body

• HTML: Rich formatted content
• RTF: Outlook's native format
• Plain Text: Simple text version
• Inline Images: Embedded pictures
• Signatures: Email signatures

📎

Attachments

• Files: Documents, spreadsheets
• Images: Photos, screenshots
• Nested MSG: Forwarded emails
• Embedded: Inline attachments
• Preview: View without saving

🏷️

Outlook Properties

• Categories: Color labels
• Flags: Follow-up markers
• Importance: Priority level
• Sensitivity: Confidential marking
• Voting: Response options

🔍

Transport Headers

• Message-ID: Unique identifier
• Received: Server routing
• X-Headers: Custom headers
• Return-Path: Bounce address
• SPF/DKIM: Authentication

Common Questions

MSG Viewer FAQ

To open MSG files without Outlook:

Download Univik MSG Viewer (free) from this page
Install and launch the application
Double-click any MSG file, or drag files into the window
View the complete email with all Outlook formatting preserved

MSG Viewer reads the proprietary Outlook format directly — no Outlook installation or Microsoft 365 subscription required.

MSG is Microsoft's proprietary email format used by Outlook. It's fundamentally different from standard email formats:

Binary format: MSG files use OLE Compound Document structure (like .doc files), not plain text
Outlook-specific: Contains MAPI properties, categories, flags, and features only Outlook understands
No standard: Unlike EML (which follows RFC 5322), MSG has no public specification

This is why Thunderbird, Windows Mail, and other email clients cannot open MSG files — they literally don't understand the format.

Aspect	MSG (Outlook)	EML (Standard)
Format	Binary (Compound File)	Plain text (RFC 5322)
Created by	Microsoft Outlook only	Most email clients
Portable	Requires special software	Opens in any email client
Outlook features	Categories, flags, voting	Not supported

If you have EML files instead, use our EML Viewer.

Yes! Unlike basic MSG readers, Univik MSG Viewer displays all Outlook-specific properties:

Color categories — Red, Blue, Green, Yellow, Purple, Orange and custom categories
Follow-up flags — Flag status, due date, reminder time
Importance — High, Normal, Low priority levels
Sensitivity — Normal, Personal, Private, Confidential
Voting buttons — Vote options and recorded responses
Read/delivery receipts — Request status and responses

Yes! When an Outlook user forwards an email as an attachment, the forwarded email becomes an MSG file inside another MSG file. This can happen multiple times, creating deeply nested structures.

MSG Viewer handles all levels of nesting. You can view the parent email and click on any embedded MSG attachment to open it in a new tab — navigating through the entire email chain.

Yes! MSG Viewer supports batch processing:

Add Folder: Load all MSG files from a directory including subfolders
Multiple Select: Select multiple files in the "Add Files" dialog
Drag & Drop: Drag multiple MSG files or entire folders into the window

Once loaded, you can search across all messages, sort by various fields, and browse them in a unified list.

MSG Viewer is designed for viewing MSG files. You can save attachments and print emails, but full format conversion is not included.

For converting MSG to PST, EML, PDF, MBOX, or other formats, use our MSG Converter tool which offers comprehensive export options.

Yes! MSG Viewer is designed with forensic use in mind:

Read-only: Never modifies original MSG files
Complete headers: Full access to transport headers and routing information
MAPI properties: View all underlying metadata and timestamps
Attachment integrity: Extract attachments without modification
No network: Works completely offline after installation

Many legal professionals and forensic investigators use MSG Viewer to examine email evidence without risking modification.

MSG Viewer is currently a Windows application. For Mac users who need to view MSG files without Outlook, you have a few options:

Use Boot Camp or Parallels to run Windows and MSG Viewer
Use our web-based viewer (if available) for quick access
Convert MSG to EML using our converter, then open in Mac Mail

We're actively working on a native Mac version — stay tuned!

Absolutely. MSG Viewer is designed with privacy as a core principle:

100% Local Processing: All MSG files are processed on your computer only
No Upload Required: Your emails never leave your machine
No Cloud Connection: Works completely offline after installation
No Tracking: We don't collect any data about your emails

Your confidential emails remain confidential — we never see them.

Yes! Once installed, MSG Viewer works completely offline:

No internet connection required to open MSG files
All processing happens locally on your computer
Perfect for air-gapped systems and secure environments
No dependency on cloud services or online authentication

MSG Viewer includes robust error handling that can often recover content from partially damaged MSG files:

Partial Recovery: Extracts readable content even from corrupted files
Header Salvage: May recover sender/recipient info when body is damaged
Attachment Recovery: Can sometimes extract attachments from damaged messages

For severely corrupted files, results vary — but MSG Viewer often succeeds where Outlook fails to open the file entirely.

View All FAQs →

Real-World Scenarios

Why People Use MSG Viewer

No Outlook License

"My colleague sent me an MSG file but I don't have Microsoft 365. I'm not paying $150/year just to read one email. MSG Viewer opens it for free."

MSG Email Attachments

"Clients forward me emails as MSG attachments all the time. I use Thunderbird, so I can't open them directly. MSG Viewer solves this problem instantly."

Legal Discovery

"In litigation, we receive thousands of MSG files as evidence. MSG Viewer's read-only mode lets us examine emails without any risk of modification — crucial for chain of custody."

Archived Outlook Emails

"I have years of old MSG files from when I used Outlook. Now I use Gmail, but MSG Viewer lets me access those archives whenever I need to find something."

IT Support & Helpdesk

"Users send us MSG files to troubleshoot email issues. I don't want to import every MSG into my Outlook just to read it. MSG Viewer lets me quickly check without cluttering my mailbox."

Home Computer

"Work uses Outlook, home doesn't. When I need to review a work email at home, MSG Viewer lets me open it on my personal computer without installing Office."

Download Free MSG Viewer

Open Outlook MSG files instantly without Microsoft Outlook.

Download MSG Viewer — Free

Version 6.1 | 14 MB | Windows 7/8/10/11 | No Outlook required

Outlook Format

Categories & Flags

Read-Only Safe

Safe & Private

Your Emails Stay Private

MSG Viewer is designed with security and privacy as core principles.

Read-Only Viewing

MSG Viewer never modifies your original files. Every MSG file remains exactly as it was — bit-for-bit identical.

No Upload Required

Your emails never leave your computer. All processing happens locally — no cloud servers, no data transmission.

Works Offline

After installation, MSG Viewer works completely offline. No internet connection needed to view your emails.

Privacy First

No tracking, no analytics on your email content. Your confidential emails stay confidential.

✓

Perfect for Forensic & Legal Use

MSG Viewer's read-only design ensures evidence integrity. Files are never modified, making it ideal for eDiscovery, litigation support, HR investigations, and compliance audits where chain of custody matters.

Why Choose MSG Viewer?

MSG Viewer vs Microsoft Outlook

You don't need a $150/year subscription just to read an email.

Comparison	MSG Viewer	Microsoft Outlook
Cost	$0 — Free Forever	$150+/year (Microsoft 365)
Installation Size	14 MB	~4 GB (full Office)
Startup Time	~2 seconds	15-30 seconds
Email Account Required?	✓ No	Yes (for full features)
Microsoft Account Required?	✓ No	Yes
Read-Only Safe Viewing	✓ Always	Can modify files
Batch Open Multiple MSG	✓ Yes	One at a time
Works Offline	✓ Yes	Limited features
Purpose	View MSG files quickly	Full email client

Bottom line: If you just need to view MSG files — not send emails or manage a mailbox — MSG Viewer does the job faster, simpler, and without any cost.

Technical Deep Dive

RTF vs HTML vs Plain Text

Understanding how MSG files store email content — and why it matters.

💡 Did you know? A single MSG file can contain the same email body in up to three different formats simultaneously. MSG Viewer intelligently selects the best format for display.

HTML Most Common

HTML Body

Standard web-formatted email content with full styling, images, links, and tables.

Best for:

Newsletters & marketing emails
Rich formatted messages
Emails with inline images

RTF Outlook Native

RTF Body

Rich Text Format — Outlook's internal format that preserves special Outlook features.

Contains:

Outlook formatting specifics
Embedded objects
Special characters & fonts

TEXT Universal Fallback

Plain Text

Simple unformatted text — always included as a fallback for maximum compatibility.

Useful for:

Quick content scanning
Copy-paste operations
Accessibility readers

How MSG Viewer Handles Multiple Formats

Detects all available body formats in the MSG file

Prioritizes HTML for best visual rendering

Lets you switch between formats if needed

Outlook-Specific Features

Access All Outlook Properties

MSG files contain features unique to Outlook. Our viewer exposes them all.

🏷️

Follow-up Flags

Flag status & due dates

⚡

Importance

High, Normal, Low priority

🔒

Sensitivity

Private, Confidential

✓

Voting

Vote options & responses

📧

Headers

Full MAPI properties

✓ Complete Outlook Fidelity: MSG Viewer displays these properties exactly as they appear in Outlook — something most basic MSG readers completely ignore.

See It In Action

MSG Viewer Interface

Clean, intuitive design focused on one thing: reading MSG files quickly.

[Screenshot: Message List]

Message List Panel

Browse all loaded MSG files in an inbox-style list with sender, subject, and date columns.

[Screenshot: Email Preview]

Email Content View

Full HTML/RTF rendering with inline images, formatting, and clickable links preserved.

[Screenshot: Attachments]

Attachment Panel

Preview images, PDFs directly. Save individual files or extract all attachments at once.

[Screenshot: Headers]

Header Analysis

View complete transport headers, routing info, and MAPI properties for investigations.

[Screenshot: Properties]

Outlook Properties

Categories, flags, importance, sensitivity, and voting options displayed clearly.

[Screenshot: Search]

Search & Filter

Find specific emails across all loaded MSG files by sender, subject, or keywords.

Technical Details

System Requirements & MSG Support

System Requirements

OS	Windows 7, 8, 8.1, 10, 11
Architecture	32-bit and 64-bit
RAM	2 GB minimum
Disk Space	60 MB for installation
.NET Framework	4.5 or higher
Outlook Required?	No

MSG Format Support

Unicode MSG	✓ Supported
ANSI MSG	✓ Supported
Nested MSG	✓ Supported
RTF Body	✓ Full Render
HTML Body	✓ Full Render
MAPI Properties	✓ All Exposed

Supported Outlook Versions

✓ Outlook 2021

✓ Outlook 2019

✓ Outlook 2016

✓ Outlook 2013

✓ Outlook 2010

✓ Outlook 2007

✓ Outlook 365

✓ Outlook 2003

✓ Outlook XP/2002

Related Tools

Need more than just viewing? Check out these related products.

MSG Converter

Convert MSG to PST, EML, PDF, and 15+ other formats.

Learn More →

EML Viewer

Open standard EML email files without any email client.

Learn More →

Universal File Viewer

View 50+ file formats including MSG, EML, MBOX, PST.

Learn More →

Need Help with MSG Files?

Our support team is here to help with Outlook MSG files, attachments, nested emails, or any other MSG-related questions.

Connect with Expert

Univik MSG File ViewerOpen Outlook Emails Without Outlook

Why MSG Files Are Hard to Open

❌ No Outlook Installed

❌ Proprietary Binary Format

❌ Outlook-Specific Features

❌ Nested MSG Attachments

❌ RTF and HTML Content

❌ Quick Review Without Import

MSG Viewer Facts

What MSG Viewer Can Do

Open Without Outlook

Outlook Categories & Flags

Nested MSG Files

RTF & HTML Rendering

Attachment Preview

Voting Responses

MAPI Properties

Search & Filter

Read-Only Safety

How to Open MSG Files

Step 1: Download MSG Viewer

Step 2: Install and Launch

Step 3: Open MSG Files

Step 4: View Complete Email

What is an MSG File?

MSG = Outlook Message Format

Why MSG Files Are Different

MSG File Facts

Corporate Email Archives

Legal Evidence

Email Attachments

What's Inside an MSG File?

Email Headers

Date & Time

Message Body

Attachments

Outlook Properties

Transport Headers

MSG Viewer FAQ

How can I open MSG files without Microsoft Outlook?

What is an MSG file and why can't regular programs open it?

What's the difference between MSG and EML files?

Can I view Outlook categories, flags, and voting buttons?

Can MSG Viewer open nested MSG files (emails inside emails)?

Can I open multiple MSG files at once?

Can I convert MSG files to other formats?

Is MSG Viewer suitable for forensic and legal review?

Can I view MSG files on Mac without Outlook?

Is my email data private when using MSG Viewer?

Does MSG Viewer work offline without internet?

Can MSG Viewer open damaged or corrupted MSG files?

Why People Use MSG Viewer

No Outlook License

MSG Email Attachments

Legal Discovery

Archived Outlook Emails

IT Support & Helpdesk

Home Computer

Download Free MSG Viewer

Your Emails Stay Private

Read-Only Viewing

No Upload Required

Works Offline

Privacy First

Perfect for Forensic & Legal Use

MSG Viewer vs Microsoft Outlook

RTF vs HTML vs Plain Text

HTML Body

RTF Body

Plain Text

How MSG Viewer Handles Multiple Formats

Access All Outlook Properties

Categories

Follow-up Flags

Importance

Sensitivity

Voting

Headers

MSG Viewer Interface

Message List Panel

Univik MSG File Viewer
Open Outlook Emails Without Outlook