Get your attachments out of winmail.dat
You were expecting a PDF, a spreadsheet or some photos. Instead the email has a single attachment called winmail.dat (sometimes ATT00001.dat), and nothing on your computer opens it. The files you need are almost always inside it. Outlook packed them into its own container format, and your mail app doesn't know how to unpack it.
Drop the file here and InboxVue unpacks it in your browser. You get every attachment back with its original name, plus the message text, which Outlook often hides inside the container as well.
What InboxVue extracts
- Attachments with their original long file names, including names in non-Latin scripts, plus their sizes and dates.
- The message body. Outlook usually stores the formatted text in the container as compressed rich text. InboxVue decompresses it and shows it as HTML or formatted text.
- Embedded emails and calendar items that the sender attached, which you can open as messages.
- Nested containers. A winmail.dat can occasionally contain another one, and those are unpacked too.
If the original email is in your inbox as an .eml file (for example, downloaded with Gmail's Download message), drop the whole email instead. The viewer shows the message and unpacks the winmail.dat attachment automatically, so you see everything in one place.
Why this happens
Outlook can send messages in HTML, plain text or its own Rich Text Format. When a message goes out in Rich Text Format, Outlook or Exchange wraps the formatting and the attachments into a TNEF stream called winmail.dat. Recipients using Outlook never notice. Recipients using Apple Mail, Gmail, Thunderbird or most phone apps see the raw container. The fix is on the sender's side. You can read the full explanation and the exact settings to send them in our guide: what is winmail.dat and how to stop it.
Troubleshooting
"No attachments found." Some winmail.dat files only carry the formatted message text and no files. The text is shown in the reading pane.
The file isn't recognised. Real TNEF files start with a fixed signature. If yours doesn't, it's probably not a winmail.dat container. ATT00001-style names are often given to ordinary text parts. InboxVue shows the content as text so you can check.
An extracted file won't open. The container doesn't change files, so an extracted .docx or .xlsx needs an app that opens that format. Images, PDFs and text files preview right here.
The sender's message was a meeting request. You'll see an event card with the date, time and location, and you can download it as an .ics file for your calendar.
Compared with other winmail.dat tools
| Tool | Platform | Upload needed | Extracts message text | Notes |
|---|---|---|---|---|
| InboxVue | Any browser, including phones | No | Yes, including compressed RTF | Free |
| Upload-based winmail.dat sites | Browser | Yes | Usually attachments only | Your attachments pass through their server |
| Desktop TNEF utilities | Windows or macOS | No | Varies | Install required; some are paid |
| Asking the sender to resend | Any | No | Yes | Works, but takes time |
If what you actually received is an Outlook .msg file, use the MSG viewer. For a standard email file, use the EML viewer.