Outlook sends attachments as Winmail.dat

imageQ: Many of my colleagues tell me that when I send them a PDF file as it comes to them as a file called winmail.dat. They try to open it but are never successful in being able to see the PDF.  What are they doing wrong?

A:  it’s very likely they’re not doing anything wrong. It’s quite possible your email client is telling the PDF to be sant in a format they can read.  I suspect your using Microsoft Outlook to send the email.  Out of the box outlook wants to send email in the default Microsoft RTF exchange outlook format. If the person your sending to has Outlook, they don’t have an issue.  If the mail provider has software to convert this on the fly, they don’t have a problem either. But some mail providers, particularly local Internet service providers, don’t do this and send the email in whatever form it comes in.

Fortunately, the solution is extremely simple.  All you need to do is change your settings to send mail in a more common format that doesn’t require conversion.  Here are the steps:

  1. Open up your Outlook email client.
  2. Click on File located in the upper toolbar.
  3. Select the Options setting.
  4. From here, select the Mail category.
  5. Now, under Compose messages, you want to ensure the HTML or Plain Text option is selected for the Compose messages in this format.
  6. Next, underMessage format, set When sending messages in Rich text format to Internet recipients to Convert to HTML format or Plain Test format
  7. Click OK to finish.

If that doesn’t solve the problem,Microsoft has a technical note that might assist. Here’s a link to it.