Winmail.dat Attachment

The radiology department at our company sends billing information via email to an outside vendor at the close of each day.  Due to the fact that this is HIPAA protected PHI we have to encrypt the email when it is sent.

We are using Microsoft Outlook 2010/2013, Exchange 2007 and a Sophos ES1100 email encryption appliance.  We scan all of the documentation into a PDF file and attach it to an email, marking the email as confidential.

When the Sophos appliance sees the "Confidential" sensitivity setting it will encrypt the email and then send it.

The recipient is using Gmail Business for their corporate email.  When the email arrives it has a "winmail.dat" attachment instead of the *.pdf format.

If I send the same email to my Personal Gmail account I receive the *.pdf attachment as I should.

I have set our clients to send as "Plain Text" and "HTML", resent both ways and the same thing happens.

This company we send to is the only recipients that have an issue with the "winmail.dat" deal.

Does anyone have a clue what is going on?
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lrmcenterConnect With a Mentor Author Commented:
We could never figure out the issues with the other companies email problem but the good news in we no longer contract with them.

Thanks to all for the input on the subject.
In Office 2010 on the client try this and see if it helps....

windows key + r

Type: regedit

Navigate:  HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Preferences

On the right pane: right-click ---> New ---> DWORD Value
Type: DisableTNEF and press Enter

Set the Value to 1 and click OK.
Exit registry editor and restart the computer and test.

I hopes this helps
lrmcenterAuthor Commented:

Tried the registry hack and it didn't help.

They still received a "winmail.dat" file BUT I still receive a *.pdf file.  The only difference is I am testing with my personal gmail account and they are using Gmail Business.
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Per this link PDF being received as winmail.dat

Outlook generates and attaches a winmail.dat file at the end of each message that only Outlook can use. It's put at the end of the message so that on the receiving side Outlook can display the message correctly. This file is typically very small, and may or may not include the original attachment. However, Outlook is the only email program that can use this information. Therefore, recipients using email clients other than Outlook might receive the winmail.dat file instead of the original message.

Taking that in to consideration they will have to disable TNEF on their side.  

What happens when you scan to pdf and attach it to your personal email and send it to them.  I thinking it will not convert the pdf to a winmail.dat file?

Just my thoughts and analysis.....
Please, look in settings Transport Neutral Encapsulation Format (TNEF)
lrmcenterAuthor Commented:
Nothing seems to work properly for that account.  I can receive perfectly in Gmail, Hotmail and my IiCloud Mail.

I just sent the email to another friend using the Gmail hosted email and his worked like it should.

It seems the only one having the problem is the company we send the billing to who is using the Gmail/Google hosted email.
It is an TNEF issue on the recipient side; maybe they need to contact Google to figure out how to enable TNEF compatilibity.

Does your friend know how he/she Gmail/Google host is configured?
lrmcenterAuthor Commented:
Their IT department/Consultant says the problem is on my end ... I figured after 35 years of doing this I would have some idea how to do deductive reasoning ...
Can you install Thunderbird and connect it to your Exchange Server and send a test document; at least it will straiten the area of possibilities?
lrmcenterAuthor Commented:
I have been trying to do just that.  Having a few issues with Thunderbird sending to the Sophos appliance.

Will post after I get the test done.
I had a similar problem but desktop outlook 2013 was sending attachments or included images as a winmail.dat attachment instead of the actual attachment.

Was extremely frustrated and almost switched mail apps then found a fix independently but also now see see Biniek referenced the same article above.

This worked for us in Outlook 2013 Win 8.1 modified registry to include

lrmcenterAuthor Commented:
We changed billing companies and now do encrypted communications using eBridge.
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