How to Fix the Outlook Winmail.dat Attachment Issue

If you’ve encountered the dreaded winmail.dat attachment issue in MS Outlook, you’re not alone. Many users struggle with this problem across different versions of Outlook, and it can be frustrating to deal with, especially when you’re trying to send important attachments. In this blog, we’ll walk you through why this issue happens and share effective solutions to fix it. By the end of this, you’ll know how to prevent your Outlook emails from sending those pesky winmail.dat files instead of the attachments you intended.

Introduction

When you create a new email in MS Outlook, you can format it in one of three ways: HTML, Plain Text, or Rich Text Format (RTF). While HTML and Plain Text typically don’t cause problems, using Rich Text Format often leads to the winmail.dat attachment issue.

But what is this winmail.dat file? Essentially, it’s a file that contains formatting information (like font styles, colors, etc.) for your email. It only attaches itself when you use Rich Text Format, and it’s mainly a problem because not all email applications can interpret it correctly. As a result, recipients may see a winmail.dat file instead of your intended attachments.

Why does the winmail.dat issue occur?

The main reason for this problem is the incompatibility of Rich Text Format across different email platforms. Most email clients, like Gmail or Apple Mail, don’t understand the formatting, so they receive it as an unreadable winmail.dat file instead. Fortunately, there are simple ways to fix this problem by changing your Outlook settings or through other technical methods.

How to Fix winmail.dat Email Attachments Issue in MS Outlook

There are a few ways to resolve this issue, depending on the version of Outlook you’re using. Here’s a step-by-step guide on how to address it.

1. Fix winmail.dat in Outlook 2010, 2013, and 2016

For Newer Versions of Outlook (2010, 2013, 2016):

1. Open MS Outlook.
2. Go to File > Options.
3. In the left column, click on Mail.
4. Under Compose messages, change the format to either HTML or Plain Text (instead of Rich Text).
5. Scroll down to Message format, and under Internet format, set the option for Rich Text messages to Convert to Plain Text.
6. Click OK to save your changes.

For Outlook 2003 – 2007:

1. Launch Outlook.
2. Click Tools > Options.
3. Select the Mail Format tab.
4. Change the Compose in this message format dropdown to Plain Text.
5. Click OK to save your changes.

2. Resolve winmail.dat Issue Using Windows Registry Editor

For a more advanced solution, you can use the Windows Registry Editor to fix the issue:

1. Press Win + R and type “regedit” to open the Registry Editor.
2. Navigate to: HKEY_CURRENT_USER\Software\Microsoft\Office\<version number>\Outlook\Preferences.
3. Right-click the Preferences folder, and create a new DWORD (32-bit) value.
4. Name it DisableTNEF.
5. Set the Value Data to 1 (with Hexadecimal as the base).
6. Close the Registry Editor.

3. Professional Tool to Resolve winmail.dat Email Attachments

If these solutions don’t work, or if you suspect the issue might be due to a corrupted PST file, a third-party tool like SoftMagnat PST Recovery can help. This tool repairs corrupted PST files and restores mailbox data to its original state, resolving any issues that may be causing Outlook to send winmail.dat attachments.

Conclusion

The winmail.dat attachment issue is usually caused by using Rich Text Format when composing emails in Outlook. Switching to HTML or Plain Text will solve the problem in most cases. However, if the issue persists, it might be related to a corrupted PST file, in which case a professional Outlook recovery tool can come in handy. By following these steps, you should be able to stop Outlook from sending winmail.dat attachments once and for all.

FAQs

1. Why does my Outlook send winmail.dat files instead of attachments?
Outlook sends winmail.dat files when you compose emails using Rich Text Format. Not all email clients can interpret this format, which is why the file gets attached.

2. How can I stop Outlook from sending winmail.dat attachments?
You can stop this by changing the message format in Outlook from Rich Text to HTML or Plain Text.

3. Is it possible to recover emails affected by the winmail.dat issue?
Yes, if the problem is due to a corrupted PST file, you can use a tool like SoftMagnat PST Recovery to recover your emails and fix the attachment issue.

4. Will changing my email format affect how my emails look to others?
Switching to HTML or Plain Text may slightly alter the visual formatting of your emails, but it will prevent the winmail.dat attachment issue.

5. Can this issue happen in Outlook.com or other web-based email platforms?
No, the winmail.dat issue is specific to the Outlook desktop application and doesn’t occur in web-based email platforms like Outlook.com.