Open a winmail.dat file
A winmail.dat is an envelope made by Outlook, holding the attachments and formatting of a message. Drop it: the files inside come out with their names, ready to save.
Or drop a winmail.dat, or the email that carries it here. Nothing is uploaded: the files stay in this tab.
When to use it
A correspondent using Outlook sends a message with attachments, and all you get is a winmail.dat file (or ATT00001.dat) that neither Gmail, Apple Mail nor Thunderbird can open.
Outlook sent the message in its own format (TNEF, "Rich Text" in its settings) instead of the standard one. The sender can change that setting; meanwhile, the files are inside the winmail.dat, and they can be taken out.
What this tool does
- The attachments inside the envelope, with their original names and sizes.
- The message body when the envelope carries it, as RTF or HTML.
- An Outlook message attached inside the envelope, opened in turn.
- A winmail.dat still inside its email: drop the whole .eml or .msg, and the envelope is opened on the way.
What it does not do: An envelope that only carries the message formatting, with no attachment, gives back only the text. The Outlook setting that produces these files is changed on the sender's side, not here.
What it reads
- winmail.dat,
ATT00001.datand anyapplication/ms-tnefattachment. - An .eml or .msg that contains a winmail.dat.
No file is uploaded: the message is read by your browser, in this tab, and the page is not allowed to open a connection to any other site.
Frequently asked questions
- What is a winmail.dat file?
- A TNEF envelope, specific to Outlook and Exchange, that carries the attachments and formatting of a message. Other software cannot read it and shows it as an unknown attachment.
- How do I stop receiving them?
- The setting is on the sender's side: in Outlook, send as HTML or plain text rather than "Rich Text" to outside addresses.
- Is the winmail.dat sent to a server to be decoded?
- No. It is opened in your browser, and the extracted files go from the tab's memory to your disk.
Other tools
- Open a .msg file : An email saved from Outlook, read without Outlook: header, body, attachments.
- Open an .eml file : The standard email format, and Apple Mail's .emlx: every encoding, every part.
- Open a PST file : A whole Outlook mailbox (.pst, .ost): its folders, its messages, search and filters.
- Open an mbox mailbox : An mbox mailbox (Gmail via Google Takeout, Thunderbird): labels, search, attachments.
- Read a WhatsApp chat : An exported WhatsApp chat, as bubbles, with its media, and an extract that says what it leaves out.