How To

How to Prevent Outlook From Sending Winmail.dat Expertly?

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Summary: Are you fed up with emails with the strange `winmail.dat` files appearing in recipients’ inbox? This annoying phenomenon occurs when emails are sent as Rich Text documents as opposed to regular HTML or plain text. The good news is that it’s possible to stop this process by changing the settings of your email client or applying some quick fixes for this issue. Follow the guide below for detailed instructions on how to prevent Outlook from sending winmail.data file and avoid this issue in the future!

What is winmail.dat File?

Have you ever opened an email sent through the Microsoft Outlook app and found an attachment named winmail.dat, that doesn’t open? The issue arises mostly because of Outlook’s certain in-built features. When it formats messages in a special format (the Rich Text format), it employs Transport Neutral Encapsulation Format (TNEF).

Normally instead of sending its emails in plain text or HTML format, it sends the visual formats used in emails as a component of a special technical packet. For example, the colors of the font used, the size of font, the images included in the email etc., are sent as one technical packet that is called TNEF.

When receiving this mail on a non-Microsoft application like Gmail, the TNEF mail format is not interpreted correctly by Gmail. The worst part is that other actual attachments may also get caught up in this format and also become impossible to access from Gmail which becomes its biggest demerit.

How to Prevent Outlook From Sending Winmail.dat?

Here is a comprehensive and systematic guide to prevent Microsoft Outlook from sending winmail.dat attachments.

Method 1: Alter the Email Format for Each Message

If you always want to ensure your email does not being sent with TNEF format:

1. Open the email you want to write.
2. Select the Format Text option from the top ribbon.
3. In the Format picture gallery, click on HTML or Plain Text (ensure that Rich Text is not checked).

Method 2: Make Changes in Outlook Setting for Default Format

If you wish to ensure that Outlook does not use Rich Text ever again:

1. Open Microsoft Outlook, then click on File option from top left corner.
2. Now select Options tab located at the bottom left side of your menu.
3. Once you are in the Outlook Options window, select Mail option from the left side.
4. Look for Compose messages section of your options.
5. Then check the drop-down menu next to Compose messages in this format and change it from Rich Text format to HTML or Plain Text format.
6. Finally save the changes made.

Method 3: Resolve It for Specific Contacts

If individuals keep indicating that only mail sent to them specifically includes a winmail.dat file:

1. To begin, open your Contacts in Outlook.
2. Then double-click on the contact name of the person having the problem.
3. Now, find the user’s email address on the contact card, right-click on it, and click on Open Outlook Properties.
4. A new screen will open. In the Internet Format section, select Send Plain Text only or Send using Outlook Rich Text Format from the drop-down options instead of the Let Outlook decide the best sending format.
5. Once done, click on OK.

Method 4: Turn off TNEF Globally via Windows Registry (for Advanced Users)

In case, one wants to completely disable the feature for all other systems so that Outlook will never use it for sending mail:

Caution: Please note that doing so incorrectly can lead to instability on the system. Do so only if you have IT support.

1. Press the Windows key along with R on your keyboard to open the Run command.
2. Type regedit and hit Enter to get into the Registry Editor.
3. Navigate to the following path (depending on your Outlook version, the number 16.0 might differ, such as 15.0 for 2013 or 14.0 for 2010): HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Preferences
4. If you don’t see a folder named Preferences, right-click on Outlook, select New > Key, and name it Preferences.
5. Click on the Preferences folder, then right-click on an empty space in the right-hand panel and select New > DWORD (32-bit) Value.
6. Name the new value DisableTNEF and press Enter.
7. Double-click DisableTNEF, change its Value data to 1, and click OK.
8. Close the Registry Editor and restart Outlook.

Conclusion

It is quite simple to eliminate the frustration of having to deal with winmail.dat attachments. Merely change the Outlook formatting settings on your end. Whether you would prefer rather a simple solution of changing your default compose format to HTML or target a more specific contact-oriented solution, sending your emails in a standardized and universal format contributes to smooth communication. Setting aside some time today to make these changes can help prevent your contacts from receiving that mysterious, unopenable winmail.dat file. Rest assured, your emails and any documents that you attach will be delivered professionally.

FAQ

Q: What is the cause of winmail.dat files?

Outlook’s use of Rich Text leads to them, as this format can’t be read by other programs.

Q: Can I only fix one contact?

Yes, you can change their email settings to make sure it arrives properly.

Q: Does changing the default settings help?

Yes, by changing the default settings to HTML or Plain Text, it will no longer happen.