I have searched and searched this is getting really annoying! 

We have office 365 at our firm online and I have put almost all employees on outlook on their desktop. We have a variety of outlooks from 2003-2013. This employee now has Outlook 2013.

There are about 5 clients we are having issues with so far... If one employee sends a PDF to one of the clients that we are having the issue with it works fine. But one employee in our firm, these 5 specific clients can not receive the pdf's from her they convert to the winmail.dat  format. We all have the same domain email which is through go-daddy so it is really confusing it is just this one employee having the issue!

I tried the regedit fix, I tried the fixing the options to Plain Text and HTML, I tried changing the options on those specific contacts, I even upgraded her from 2010 to 2013 and thinking that would work! IT DID NOT!

I just now tried the deleting the contact and manually entering the email address and that works, but as many emails as this employee sends doing this every time for multiple clients is going to be a hassel. Is there a quicker fix for this that I am not seeing? any help would be greatly appreciated!

Thanks!

Hi,

If the sender saves the contacts for these 5 clients, does the issue persist? Does she need to re-create Contacts for these 5 clients every time when she sends a .pdf to them?

This issue usually occurs if the sender sends a rich text format email to a recipient who doesn't use Exchange/Outlook, then the recipient's mail system may not recognize rich text format and converts the email into a winmail.dat file. Please double confirm if the issue persists when sending as a html email.

If the issue persists, I also suggest you do a test. Let the sender sends the email with .pdf from the web-based email, and the recipient also checks the email from the web, does the issue exist? This helps determine whether the conversion happens on the client or the server.

Please go through all the points above and let me know the result. If I misunderstood anything, feel free to let me know.

Regards,

Melon Chen
TechNet Community Su

I really must have just lost my brain for a moment. She said that she has been deleting and re-saving them and after just one time of doing so they are getting the PDF's. So I guess the issue is fixed. 

Thanks!

If she continues to have problems, you can change the remote domain settings on the server - but when you do this, features that use TNEF data won't work (task requests, some meeting requests). You can create remote domains for specific domains rather than changing it for all.

More information and instructions are here - http://www.slipstick.com/exchange/cmdlets/blocking-tnef-exchange-server/