Got a winmail.dat attachment you can't open? It's a Microsoft format that Mac email clients can't read. Drop it here to decode it and get your attachments.
Drop file here
or click to browse
Winmail.dat is created by Microsoft Outlook on Windows when it sends emails in Rich Text Format (RTF). Outlook bundles the email body and attachments into a TNEF (Transport Neutral Encapsulation Format) file and names it winmail.dat.
Mac email clients — Apple Mail, Spark, Airmail, Mimestream — cannot decode TNEF. So instead of seeing your actual attachments (a Word doc, a PDF, a photo), you see a mysterious winmail.dat file.
Save the winmail.dat file
Save the attachment from your email client to your Mac — it will be named winmail.dat.
Drop it on MailSnap
Drag winmail.dat onto the drop zone above, or click to browse.
Get your attachments
MailSnap decodes the file and lists all attachments. Download each one individually.
What is a winmail.dat file?
Winmail.dat is a TNEF file created by Outlook on Windows when sending Rich Text emails. It wraps the real email content and attachments in a proprietary binary format.
Why am I getting winmail.dat on my Mac?
The sender uses Outlook on Windows with Rich Text Format enabled. Mac email clients cannot decode TNEF, so you see winmail.dat instead of the actual attachments.
Is MailSnap free?
Yes, completely free. No account, no file size limit, no upload.
Can I stop receiving winmail.dat?
The fix is on the sender's end — they need to send HTML or Plain Text instead of Rich Text in Outlook.