What can I do with a "winmail.dat" error?

If email attachments are appearing as "winmail.dat" at the recipient's end, Rich Text Formatting (RTF) may be enabled in your Outlook.

To resolve this issue, please complete the two steps below:

1. Confirm RTF is not set as the default formatting setting for outgoing mail.
2. Confirm RTF is not set as the contact-specific formatting setting for outgoing mail.

Default Formatting Setting

• In Outlook, select File > Options.
• Select the Mail tab.
• Under "Compose messages", next to "Compose messages in this format", select either "HTML" or Plain Text", but NOT "Rich Text".
• Scroll down and under "Message format", select either "Convert to HTML format" or "Convert to Plain Text format", but NOT "Send using Outlook Rich Text Format".
• Click OK.

Contact-Specific Formatting Setting

Contact-specific formatting settings override default formatting settings, so it is important to clear the auto-complete cache.

• In Outlook, select File > Options.
• Select the Mail tab.
• Under "Send messages", click "Empty Auto-Complete List".
• Click OK.