Open winmail.dat files in your browser
The attachment Outlook sends in place of the real ones, when the email reaches a mail app that isn't Outlook. Open it right here as the files it holds. Nothing leaves your device.
Or drop it anywhere on this page
What you'll see
Your winmail.dat opens like a folder, the email Outlook wrapped and the files attached to it listed on the left.
- The email • Its text from Outlook's rich text
- Attachments • Each opens on its own
- Meetings • In the agenda
- Export • Save as ZIP or Extract all
About winmail.dat
Outlook can send an email's formatting, its meeting details and its attachments wrapped in one attachment of its own, named winmail.dat, in Microsoft's Transport Neutral Encapsulation Format. Outlook unwraps it, and every other mail app shows a file nobody can open.
It happens when Outlook sends rich text to someone outside the company, or when an Exchange server is set to send it. Apple Mail, Gmail and phones get winmail.dat in place of the PDF or the photos they were sent.
Filepeek opens it as a folder: the email Outlook wrapped, with its text from the rich text, and each attached file in its own viewer. A meeting opens in the agenda. Save as ZIP or Extract all saves them all.
winmail.dat, Outlook's Transport Neutral Encapsulation Format
.tnef
Format
- MIME type
- application/ms-tnef
- Made by
- Microsoft
- Released
- 1990s
Inside the file
- Subject, text and rich text
- Attachments
- The files that were sent, emails too
- Meetings
- When and where
- Written by
- Outlook and Exchange
Opens in every browser
Browsers download winmail.dat, and only Outlook unwraps it. Filepeek opens it in Chrome, Edge, Firefox and Safari.
- YouChromeOpens through Filepeek
- YouEdgeOpens through Filepeek
- YouFirefoxOpens through Filepeek
- YouSafariOpens through Filepeek
Questions
How do I open winmail.dat?
Drop it on this page or choose Peek a winmail.dat. The email and the files attached to it are listed on the left, each opening in its own viewer.
Why did I get winmail.dat instead of my attachments?
The sender's Outlook wrapped the email in Microsoft's own format, which only Outlook unwraps. The attachments are inside it, and they open here.
Can I open a winmail.dat that came in an email?
Yes. Open the email here, then click winmail.dat among its attachments, and it opens as the files it holds.
Is my file uploaded?
No. The file opens inside your browser and never leaves your device.