---
title: "Prevent Outlook from Sending the Winmail.dat File"
description: "Microsoft Outlook is a widely used email client that will often take emails that were created or formatted using Rich Text and then automatically store the formatting data into a file named..."
url: https://www.inmotionhosting.com/support/email/outlook/prevent-winmaildat/
date: 2013-04-03
modified: 2021-12-03
author: "InMotion Hosting Contributor"
categories: ["Outlook"]
type: post
lang: en
---

# Prevent Outlook from Sending the Winmail.dat File

![](https://www.inmotionhosting.com/support/wp-content/uploads/2021/12/winmaildatfile-1024x538.png)

**Microsoft Outlook** is a widely used email client that will often take emails that were created or formatted using **Rich Text** and then automatically store the formatting data into a file named **winmail.dat**. This file is then attached to the email that you are sending. You can avoid this by using **HTML **or **Plain Text** when composing emails. Follow the directions in our guide below to learn how you can configure **Outlook **to stop this issue.

- [Configure **Outlook **to prevent Winmail.dat](#prevent)
- [Change settings for individual contacts](#contacts)

## Prevent the Winmail.dat file attachment with Outlook Settings Changes

All of the steps below do require that you have access to the **Outlook** client settings. If your access levels prevent you from making these changes then you will need to speak with your administrator before these changes can be made.

1. Login to **Outlook**, then click on **File** to go to the **Account Information** page. Click on **Options**.![windows account information](https://www.inmotionhosting.com/support/wp-content/uploads/2013/04/01-preventwinmaildat.png)
2. Next, in the column at left click on **Mail**. Then go to the section labeled *Compose messages*. In the drop-down menu next to *Compose messages in this format*, click on **HTML **or** Plain Text**. Any messages that you compose will automatically be set to this format.![windows selection](https://www.inmotionhosting.com/support/wp-content/uploads/2013/04/02-preventwinmaildat.png)
3. After you have set your message composer to use HTML, we have to go the **Message format** section for one other setting. Scroll down until you find *When sending messages in Rich Text format to Internet recipients*. Click on the drop-down menu and make sure that it set to **Convert to HTML format**. Click **OK **when you’re done with your changes in order to save your settings.![outlook message format](https://www.inmotionhosting.com/support/wp-content/uploads/2013/04/03-preventwinmaildat.png)

For **Outlook 2003** or **2007**, you will need to click on **Tools **to get to the **Options** menu. From there, instead of **Message Format **you will need to find **Mail Format**. Here you can select **HTML **or **Plain text** as per the instructions above.

These changes are being made so that **Outlook **doesn’t send or convert messages to **Rich Text**. The instructions should work in recent versions of **Outlook **but won’t work in **Outlook 2016** and **2019 **when emails are assigned to an address book entry. You can make changes to individual contact settings to help prevent sending the winmail.dat file as per the steps below.

## Disable Winmail.dat for Individual Contacts

In order to make changes to individual contacts, you will need to be in an email that you are composing in **Outlook**.

1. Go to the **To:** field and right-click on the email address you’re sending to.
2. Select **Open Outlook Properties**.
3. Find **Internet Format**, then click on **Send Plain text only**.
4. Click on **OK **in order to save your changes.

In **Outlook 2007**, **2010**, and **2013 **you will need to go to the **Outlook Contacts**. The steps are essentially the same as above, but you are simply not composing a message.

1. Search for the contact that you want to make sure that you’re not sending a winmail.dat file.
2. Right-click on the contact (or double-click it). Select **Open Outlook Properties**.
3. Find **Internet Format**, then click on **Let Outlook decide the best sending format** or **Send Plain text only**.
4. Click on **OK **in order to save your changes.

That completes our guide on making changes to the **Outlook **email client so that you don’t send a winmail.dat file. For more information on email clients and many other topics, check out our [Email channel](https://www.inmotionhosting.com/support/email/) in the [InMotion Hosting Support Center](https://www.inmotionhosting.com/support/).

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