Is there anyway of preventing the win mail.dat thing to happen when an outlook account sends an attachment to an aol account or to a mac computer or an iPhone?  i have many users who do not use outlook and the messages they receive come this way.  I have installed wimail openers on these other computers but was wondering if there was something on the outlook sender side of things that could fix this before it is sent.
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It's usually NOT an Outlook problem, it's the Exchange server that sends the email.
Here's a MS Support document that describes this problem and also a solution:
In short, sometimes the Exchange server sends out an email in RTF format, the receiving mail server will have no way other than displaying a winmail.dat file for the user. Solution is to set your Exchange server to NEVER send as RTF (no problem, as txt and html are still viable).
mkramer777Author Commented:
we don't use exchange.  POP
In that case, check how you send out your email, in what format (TXT, RTF, HTML). Try to keep it on text or HTML.
If someone complained, use that as a starting point. Send exactly same email, but now try to change the format to TXT (could be ugly) or HTML. if the recipient now doesn't have a problem viewing it, you know what you should do (set to HTML by default)
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Jonathan BriteSystem AdminCommented:
Configuring Outlook to Not Send Winmail.dat Attachments

Outlook can use a method called Transport Neutral Encapsulation Format (TNEF) to package information for sending messages. The use of TNEF is affected by settings in Outlook that are referred to as Rich Text Format (RTF).

A TNEF-encoded message contains a plain text version of the message and a bundled binary attachment that contains the other parts of the original message. This attachment is named Winmail.dat, and includes:

    The formatted text version of the message (including fonts or colors)
    OLE objects (embedded pictures and embedded Office documents)
    Special Outlook features (custom forms and meeting requests)
    Any file attachments that were attached to the original message

Unfortunately, the Winmail.dat bundled attachment is not readable by many other email clients or by Outllook for Macintosh and it may even appear to the recipient as though the expected attachment is missing.
How to Avoid Sending Winmail.dat Attachments
Setting Global Properties

Set the Global Properties to have Outlook by default send your email in Hypertext Markup Language (HTML):

    Outlook 2007: Select Tools > Options > Email Format > Internet Options. Select Convert to HTML format.
    Outlook 2010 and 2013: Select File > Options > Mail and then scroll to the bottom of the dialog. Select Convert to HTML format.

Meeting requests or voting buttons may not work with this setting, but you can override the format on select messages.

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mkramer777Author Commented:
are all outlook accounts that I install defaulted to not send in HTML?
Jonathan BriteSystem AdminCommented:
I would think they ARE set to send in HTML by default, but there are many cases where a user makes some changes for various reasons.  No harm in taking a look to what they have it set to IMO.
mkramer777Author Commented:
Ok.  So say they have it set to HTML and it still sends to aol and mac computers as win mail, then what are my options?
Jonathan BriteSystem AdminCommented:
try the following links:
Great MS KB article
This one is basically what I already mentioned but has some additional steps.  This is also what I have successfully used in the past with our executives who love sending to aol accounts...
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