Guide
Why you got a winmail.dat file
You were sent a PDF or a spreadsheet, but all you see is winmail.dat. Here's why, and how to get the real files back.
Updated 29 October 2026 · 2 min read
What winmail.dat is
Outlook can send email in its own Rich Text format. When it does, it packs the attachments, and sometimes the formatted message, into one file called winmail.dat, using Microsoft's TNEF format.
Outlook unpacks it without anyone noticing. Apple Mail, iPhone, Android, Gmail and most other apps can't, so they show winmail.dat instead of the files that were sent. The files are still inside it.
How to get the files back
- Save winmail.dat from the email to your device.
- Open the winmail.dat opener and drop the file into the box.
- The free preview lists every file inside, with its name and size.
- Download each file, or all of them in one zip: free from one email up to 2 MB, or unlock with a pass.
The file is opened in your browser, so we never see your email or its attachments.
On an iPhone or iPad
- In Mail, press and hold winmail.dat, then choose Save to Files.
- Open openemailfile.com in Safari and tap the box.
- Tap Browse, then pick winmail.dat from where you saved it.
How the sender can stop it
The fix is on the sending side. In Outlook for Windows, the sender opens File, Options, Mail, and sets Compose messages in this format to HTML. On the same page, under Message format, they can also set Rich Text emails to internet addresses to convert to HTML.
If only one person's emails arrive this way, their Outlook may be set to send Rich Text to your address alone. Ask them to check how your address is saved in their contacts.
Is winmail.dat safe to open?
Winmail.dat itself is a normal Outlook file, not a virus. The files inside are ordinary attachments, so treat them as you would any other: open them only if you trust the sender.