OL98: (CW) Winmail.dat Attachments Included in Received Messages

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Article ID: 193118 - View products that this article applies to.
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NOTE: These procedures only apply if you have installed Outlook with the Corporate Workgroup/Other option. This option allows you to use Messaging Application Programming Interface (MAPI) services. To determine your installation type, on the Help Menu click About Microsoft Outlook. In About Microsoft Outlook you should see "Corporate" if you have the Corporate Workgroup installation.
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When you use Microsoft Outlook 98 to send e-mail containing attachments through the Internet, some recipients using e-mail clients other than Outlook, report that the mail message includes an additional file called Winmail.dat. The file is usually very small, but cannot be opened in the mail message.


The Winmail.dat file is used to preserve formatting that the sending client includes in the message, but is not recognized by the receiving client. In the case of Outlook, the Winmail.dat file includes Rich Text Formatting (RTF) instructions. This type of formatting is used with the Microsoft Outlook Rich Text Format and when using Microsoft Word as an e-mail editor.


To avoid including Winmail.dat, use the Plain Text mail format. To select Plain Text for all messages, follow these steps:
  1. On the Tools menu, click Options and then Mail Format.
  2. In "Send in this message format", click to select Plain Text.
To send to certain recipients with RTF format and others with Plain Text, you must use the Personal Address Book. To set Plain Text by recipient, follow these steps:
  1. On the Tools menu, click Address Book.
  2. In Show Names From, select the Personal Address Book.
  3. Select the addressee you wish to set as Plain Text and on the File menu, click Properties.
  4. Click to clear the "Always send to this recipient in Microsoft Exchange Rich Text Format" check box.


For more information on Winmail.dat attachments, please see the following article(s) in the Microsoft Knowledge Base:
149203 XFOR: Preventing Winmail.dat From Being Sent Over IMC

138053 XFOR: Preventing WINMAIL.DAT Sent to Internet Users


Article ID: 193118 - Last Review: October 10, 2013 - Revision: 1.0
  • Microsoft Outlook 98 Standard Edition
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