How to Fix Outlook Winmail.dat Attachments Issue in Outlook 2010, 2013, 2016

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If your MS Outlook receives a winmail.dat attachment and looking for a solution to stop it for sending winmail dat files, lets read this blog. In this blog, we will explain the Outlook winmail.dat attachment problem in various Outlook versions. We describe why the issue arises and how you can resolve it. Also, you will learn different solutions to the Winmail dat email attachment problem based on different causes.


MS Outlook creates a new email in either of the three formats: HTML format, plain text format, or rich text format. The first two formats do not cause any issue in composing a new mail. But, while choosing the Rich text format, the Winmail.dat attachment issue occurs often.

Outlook Winmail.dat attachment is a file attached with a newly created email. This file contains the formatting information of the message like bold, italic, highlight, etc. It allows other email clients to display the email in the same formatting as composed in MS Outlook. It is only attached with an email when you select the Rich Text format to create new emails.

The root cause of the winmail dat attachment issue is the incompatibility of other email clients with the Winmail.dat file. So, you are receiving winmail.dat instead of attachments in other email clients.

Now, you can resolve the problem by using other formats to compose the message. Let us see the answer to the query – how do I stop sending winmail dat files?

How to Fix the Outlook Winmail.dat Email Attachments Issue?

You can resolve the winmail dat Outlook 2013 issue by adopting various methods. In these techniques, you need to perform some simple steps. As the issue arises because of the attachment file with Rich text format, the first option to fix the problem is by choosing another format. Now, follow the steps below.

Fix Winmail.dat Outlook 2010, 2013, 2016 Using the MS Outlook Application

In the latest version of MS Outlook

  • Open the MS Outlook application in your system.
  • Click on the File button and select the Options
  • Now, choose the Mail option available in the left section.


  • After that, choose the HTML or Plain text in the Compose message in this format option.

compose message

  • Now, scroll down to the Message Format section and click on the When sending messages in Rich Text format to the Internet Recipients field.
  • Choose Convert to HTML format or Convert to Plain Text format in this option.

convert to html format

  • At last, click on the OK button to save the changes.

In Outlook 2003 – 2007

  • Launch the Outlook application in your system.
  • Click on the Tools button and select Options from the list.
  • Now, choose the Mail Format tab in the top bar.
  • In the Message Format section, expand the drop-down of the Compose in this message format
  • After that, select either HTML or Plain Text option from the list.
  • Finally, click on the OK button to save the changes and close the options wizard.

Resolve Outlook Winmail.dat Issue Using Windows Registry Editor

  • Press the Win+R button to open the run command.
  • Now, type ‘Regedit in the field and click on the OK
  • It will open the Windows Registry Editor.
  • Go to the following path in the Registry Editor.

HKEY_CURRENT_USER\Software\Microsoft\Office\<office version number>\Outlook\Preferences

  • Right-click on the Preference folder and choose the New option.

set Preference

  • After that, select the DWORD (32-bit) Value option.

choose DWORD

  • Assign the name DisableTNEF to this new registry key.
  • Now, right-click on the DisableTNEF registry key and choose the Modify option.


  • Choose the Base as Hexadecimal and Value Data as 1. Press the OK button.

set Hexadecimal

  • At last, close the Registry Editor.

The above options will fix the Outlook Winmail.dat attachments problem. However, if the problem arises because of a corrupted PST file, you can resolve the issue by using these manual techniques. You will need a professional tool to repair the damaged Outlook data file and fix the attachment issue. winmail dat email attachment

Professional Solution to Resolve Winmail.dat Email Attachments in Outlook

DRS PST Recovery tool is the ideal solution to repair the corrupted PST files. And fix the winmail dat email attachment issue in Outlook. The tool effectively repairs the damaged PST files and restores complete mailbox data to its original state. Apart from that, if any issue arises because of the corrupt Outlook PST file, the utility will fix the problem effectively.


The Outlook Winmail.dat attachments issue arises when you use the Rich text format for composing new emails in Outlook. So, the obvious solution to the problem is to choose the HTML or Plain text format instead of the rich text format. However, if Outlook receives a winmail.dat email attachment error due to corrupted PST files, you need to use a professional solution like DRS PST Recovery Tool.


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