winmail.dat (outlook,, gmail)

Posted on 2007-11-14
Last Modified: 2008-02-18
User B has 3 accounts (corporate email, and gmail).
Corporate email is setup in outlook... and gmail accounts are setup in outlook express.
When user A (using outlook) sends to user B with attachment, outlook (corporate a/c) can receive the attachment as it is. and gmail a/cs receive the attachment as winmail.dat.

User B says that its only from this particular User A that has this issue. He can receive attachment as it is in his vsnl and gmail a/cs from other people.
Question by:grnow
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Expert Comment

ID: 20287931
Winmail.dat is a notorious issue when sending email from Outlook to other clients. Here's a tool to extract attachments from winmail.dat:

One solution that worked for me is to instruct User A to to send the email as Plain Text.

If User A uses Exchange, here's Microsoft's take on the issue:

LVL 97

Assisted Solution

war1 earned 50 total points
ID: 20289981
Hello grnow,

Email clients other than Outlook has difficulty reading Outlook HTML or Plain Text emails.  So Corporate account with Outlook can read the emails, but non-Outlook clients see winmail.dat.

The best way is the have sender send in Plain Text Format, as FilipZahradnik suggested.

Hope this helps!

Author Comment

ID: 20294707
Hi, for the settings to plain text...
other than under tools->options->mail format->message format,
there is this button called 'internet format', do i need to set anything in there?

if i ask user B to setup his vsnl and gmail a/cs in outlook, will that help to resolve the issue as well?
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Accepted Solution

FilipZahradnik earned 150 total points
ID: 20294744
To set UserA's Outlook to send all emails (to any recipient) in plain text, go to Outlook, Tools->Options->Mail Format->Internet Format button. Select Convert to Plain Text.

To only use plain text format ONLY when UserA sends emails to UserB, create entries in UserA's Outlook Contacts for UserB's email addresses. Then open each contact, right-click the email address entry and select Outlook Options. There you will be able to select 'Send Plain Text only'.

Author Comment

ID: 20312479
i tired on my own a/c by setting user B 'send options' to HTML only.
he managed to receive my attachment. which is why this is the puzzling thing. i send to him in html format and he able to receive it.

Expert Comment

ID: 20316649
Indeed, the problem does not occur in majority of cases - otherwise, half the Internet would not be able to receive attachments from Outlook.

It appears that it is linked to sending email in RTF format, so using HTML might work as well as plain text.

When you select RTF format, Outlook uses TNEF to encode the message. For plainp-text or HTML it uses MIME. TNEF is Microsoft-proprietary format, hence the compatiblity issues. MIME is the Internet standard that everybody understands.

Hope this helps...

Expert Comment

ID: 20424948
Any feedback on this issue?

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