What Is an MSG File?
An MSG file is a Microsoft Outlook email message saved in a proprietary format. It contains the full email — subject line, sender, recipients, date, HTML body, embedded images, and file attachments. Outlook users can drag-and-drop or export individual messages as .msg files for archiving, sharing, or legal discovery.
The problem? Windows doesn't know how to open MSG files by default. Double-clicking a .msg file on a machine without Outlook installed results in a "How do you want to open this file?" prompt — with no useful suggestions.
Why You Might Need to Open MSG Files
There are several common scenarios where you'll encounter MSG files:
- Legal & compliance — eDiscovery document review requires opening thousands of exported emails.
- IT administration — Helpdesk teams receive forwarded emails as MSG attachments.
- Business hand-offs — Clients and partners share archived correspondence.
- Personal backups — Outlook users export important emails before migrating to another platform.
The Traditional Approach: Microsoft Outlook
The "official" way to open MSG files is with Microsoft Outlook itself. However, this comes with significant drawbacks:
- Cost — Outlook requires a Microsoft 365 subscription or a one-time Office purchase.
- Size — The full Office suite is over 500 MB.
- Overhead — You need to configure an email account even if you only want to view a single file.
For most people who just need to read an MSG file, installing Outlook is overkill.
The Better Way: OpenMSG
OpenMSG is a lightweight MSG file viewer built specifically for Windows 10 and 11. It does one thing and does it exceptionally well — opens MSG files instantly.
Key advantages:
- No Outlook required — fully standalone.
- Lightning fast — opens even large MSG files in milliseconds.
- Full rendering — displays HTML email bodies, embedded images, and attachments exactly as sent.
- Attachment extraction — save any attachment with a single click.
- Privacy-focused — MSG file processing happens locally on your device. Nothing is uploaded.
How to Install OpenMSG
Getting started takes less than 60 seconds:
- Visit the Microsoft Store listing.
- Click Get — the download starts automatically.
- Once installed, double-click any .msg file to open it with OpenMSG.
The app is under 15 MB and requires no configuration.
Setting OpenMSG as Your Default MSG Viewer
To make OpenMSG open MSG files automatically every time:
- Right-click any .msg file.
- Select Open with → Choose another app.
- Pick OpenMSG from the list.
- Tick "Always use this app to open .msg files".
From now on, double-clicking any MSG file will launch OpenMSG directly.
Common Issues and Fixes
"Windows cannot open this file"
This means no app is associated with the .msg extension. Install OpenMSG from the Microsoft Store and follow the default-app steps above.
Attachments not displaying
Make sure you're running the latest version. The Microsoft Store updates OpenMSG automatically.
Embedded images appear broken
Some MSG files reference external images that may no longer be hosted. OpenMSG will display all images that are embedded directly in the email body.
Conclusion
Opening MSG files on Windows doesn't require an expensive Outlook subscription or a bloated Office installation. OpenMSG gives you everything you need — fast and private. Download it from the Microsoft Store today and never struggle with MSG files again.