Frequently asked questions
Are my files uploaded to a server?
No. The .msg file is read directly in your browser using JavaScript. There is no upload endpoint, no storage bucket and no server-side processing. You can verify this by opening your browser's Network tab while you open a file, or by disconnecting from the internet — the viewer keeps working.
What is a .msg file?
A .msg file is Microsoft Outlook's proprietary format for a single item — an email, appointment, contact or task. It is a Compound File Binary (OLE2) container that stores the message properties, body, recipients and attachments as separate internal streams. Unlike .eml, it is not a standard format, which is why most non-Microsoft applications cannot open it.
Can I open a .msg file without Outlook?
Yes. This viewer reads the file's internal structure directly, so you do not need Outlook, a Microsoft 365 subscription or any installed software. It works on macOS, Windows, Linux, iOS and Android in any modern browser.
Does it show attachments?
Yes. Every attachment is extracted and can be downloaded individually or as a ZIP archive. Embedded messages — a .msg attached inside another .msg — can be opened in place without downloading them first.
Why are images in the message not showing?
Images hosted on a remote server are blocked by default because senders commonly use them as tracking pixels to detect when you open a message. Use the "Load images" button in the banner to fetch them. Images embedded in the file itself always display immediately.
Can I convert .msg to PDF?
Yes. Open the message and choose Print / PDF, then select "Save as PDF" as the destination. A print-ready copy of the message opens in a new window — allow pop-ups if nothing appears — carrying the full header block, the complete body across as many pages as it needs, and the attachment names.
Is there a file size limit?
Files up to 100 MB are supported, which comfortably covers messages with large attachments. The limit exists to protect your browser tab from running out of memory, not because of any server constraint.
Does it work with encrypted or signed messages?
Digitally signed messages are readable — the signature is shown as an attachment. Encrypted (S/MIME) messages cannot be decrypted without your private certificate, which the browser has no access to.