Outlook 2016 winmail.dat problem - have tried all solutions found online

Hi,

To assist you, may we know what is the path you've followed in the registry when you add the DWORD value?

In the meantime, we suggest that you change the format of your mail message to plain instead of HTML. You can follow the steps below:

1. Open Outlook, go to File -> Options -> Mail.

2. In Mail tab, look for Message format section -> When sending messages in Rich Text format to Internet recipients: -> choose the Convert to Plain Text format in the drop down box. See screenshot below:

Or you can change the Format Text to Plain Text. See screenshot below:

Let us know how it goes.

I tried the Plain Text option but it did not help. Outlook 2016 still sent attachments as winmail.dat to Mac and Thunderbird users.

I added a DWORD named "DisableTNEF" to the key HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Preferences. I set the value at 1.

Thank you for the details. For additional information, were there any changes made before the issue started happening?

If the plain text option didn't help, then you may try to reconfigure your email account in Outlook 2016. You can follow the steps below:

1. Go to Control Panel, search for Mail and select it.

2. Select your Outlook profile and Remove.

Once done, you may re-create an Outlook profile. To do so, kindly check the instructions on this link.

Regards.

I recall making no changes to my Outlook 2016 account before the winmail.dat problem began.

As you suggested, I removed my Outlook profile and re-created it. The problem still exists.

You can try to change the format of all new messages to Plain Text or HTML and check if the issue still persists.

1. On the File tab, choose Options > Mail.
2. Under Compose messages, in the Compose messages in this format list, click HTML or Plain Text.

Give us an update.

There is another thread here.  This happened when the new outlook.com system was introduced.  Microsoft seem unable to accept this and continue to give recommendations that worked in the past but don't work with this new bug.

If someone from Microsoft just said "It is a known bug and we are working on it", we would know where we are. This is really serious because it means that some recipients can't read attachments.

Bob

I finally figured out the problem i.e. The problem is with e-mail address book.

To solve this problem, you have to manually type the e-mail address of recipient instead of select from Address Book.

By this way, your attachments will receive smoothly by recipient(s) and there will be no winmail.dat

I personally tried this and found OK.

Now Microsoft only have to look why this problem is occurs. Hope they will soon find a solution of this problem.

I finally figured out the problem i.e. The problem is with e-mail address book.

To solve this problem, you have to manually type the e-mail address of recipient instead of select from Address Book.

By this way, your attachments will receive smoothly by recipient(s) and there will be no winmail.dat

I personally tried this and found OK.

Now Microsoft only have to look why this problem is occurs. Hope they will soon find a solution of this problem.

GENIUS!!!  I tried everything and nothing worked until now.  NOW we know where the problem originates!

This solved my problem for Outlook 2016.

I actually deleted the recipient contact and recreated it and it now works perfectly.

I hope that Microsoft fixes this, it is probably the most annoying and badly documented problem / bug I have faced in a while.

Thanks a lot Rafiq.