Winmail.dat file

The infamous "winmail.dat" file!

The "winmail.dat" file is a temporary file created by Microsoft Outlook when it encounters a problem sending an email with a Rich Text Format (RTF) attachment. The file is usually around 1-2 KB in size and contains the contents of the email, including the attachment.

The problem occurs when Outlook tries to send an email with an RTF attachment, but the recipient's email client or server is not configured to handle RTF attachments. This can happen when:

  1. The recipient's email client is not compatible with RTF attachments.
  2. The recipient's email server is not configured to accept RTF attachments.
  3. The email client or server is not set up to handle attachments with certain file types.

When Outlook encounters this issue, it creates a "winmail.dat" file in the sender's email account's "Sent Items" folder. The file contains the contents of the email, including the attachment, in a proprietary format that is specific to Microsoft Outlook.

The "winmail.dat" file is not a standard email attachment and is not recognized by most email clients or servers. As a result, the recipient may not be able to open or view the email or attachment.

To resolve the issue, you can try the following:

  1. Save the "winmail.dat" file to your computer and open it in a text editor to view the contents.
  2. Convert the RTF attachment to a more widely supported format, such as PDF or HTML.
  3. Check with the recipient to see if they have any specific requirements or settings that need to be adjusted to receive RTF attachments.
  4. Consider using a different email client or server that is more compatible with RTF attachments.

It's worth noting that the "winmail.dat" file is not a security threat and is not malicious in nature. It's simply a temporary file created by Outlook to help troubleshoot the issue.