Winmail.dat converter
Got a winmail.dat instead of the attachment you were waiting for? Drop it here. We unpack it right in your browser and show you every file inside, ready to preview and save.
- Nothing is uploaded. Your files never leave your device.
- Unpack lots at once, even a whole folder.
- Free, with no sign-up and no limits.
Drop your winmail.dat here
One file, many files or a whole folder.
Also opens ATT00001.dat, Outlook .msg and .eml files. You can paste files in too.
Saving more than one file gives you a single ZIP, named after the email.
Winmail.dat, explained
Short answers to the questions people ask most. Still stuck? Send us a message and a real person will help.
What is a winmail.dat file?
When someone sends an email from Microsoft Outlook in its own Rich Text format, Outlook wraps the attachments in a file called winmail.dat (sometimes ATT00001.dat). Outlook can read it, but most other email apps, like Gmail, Apple Mail and the mail app on your phone, cannot. So you get the wrapper instead of the files.
Are my files uploaded anywhere?
No. The converter runs inside your browser, on your own device. Your files never reach our server or anyone else’s. Once this page has loaded, unpacking even works without an internet connection.
Can I open more than one at a time?
Yes. Drop in as many files as you like, or a whole folder. Each email gets its own group, and you can tick the files you need and save them together as one ZIP.
Which files can it open?
winmail.dat and ATT00001.dat files, Outlook .msg files and .eml files, including emails that have a winmail.dat inside them. Emails attached inside other emails are unpacked too.
Why is there no preview for some files?
We show previews of images, PDFs, Word documents (.docx), spreadsheets, text files, audio and video. Anything else, like older .doc files or design files, can still be saved and opened on your device.
It says there is nothing inside. What now?
Some winmail.dat files only carry the email’s formatting, not attachments. Use “Read the email” to see the message itself. If you expected a file, ask the sender to send it again as a normal attachment.
How do I stop getting winmail.dat files?
The fix is on the sender’s side. In Outlook they can go to File, Options, Mail and set “Compose messages in this format” to HTML. If their company uses Microsoft 365 or Exchange, their IT person can switch off Rich Text (TNEF) for outside email. Sending them a link to this page helps.
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