The attachment was supposed to be a PDF, and instead you got winmail.dat. Your files are still in there — drop it here and get them back.
When Outlook or Exchange sends mail in its “Rich Text” format, it wraps the message and
all its attachments in a Microsoft-only container (TNEF) that nothing else can open.
Recipients outside the Outlook world see one useless winmail.dat instead of the
files that were sent. This tool opens the container and hands you what’s inside.
Every attachment, with its original filename, plus the message body where one is embedded. One file inside → you get that file directly; several → a ZIP. If the extraction finds nothing, the .dat was likely damaged in transit — ask the sender to resend as a normal attachment.
It’s the sender’s setting, not yours. Ask them to switch Outlook’s mail format from “Rich Text” to HTML or Plain Text (File → Options → Mail → Compose messages). Exchange admins can also disable TNEF for outside addresses. Until then, this page will be here.
It’s written to a private temporary folder for the few seconds the conversion engine needs, then deleted — nothing is retained, logged or shared. No account, no email, no “files kept for 24 hours” fine print. These are often someone’s letters, family records or old business files; we treat them accordingly.