How do I prevent .dat files in email. Exchange 2010

I recently have had a user complain to me that all her emails coming in from here clients with signatures (picture) and attachments are being converting in her inbox as .dat files. She can not retrieve the files and needs to send to her personal mail. She is the only one so far and do not want this to start to become a company wide issue. I read some where that there is a way to tell Exchange not to covert to dat files. any help would be completely appreciated.
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The problem with .dat files is that she is receiving emails in RTF which are then converted to HTML. In thtat process you risk having an incorrect conversion where the email contents are saved in .dat file. There are actually small tools that can open .dat files so you can retrieve the information.

Your Exchange server will by default convert anything in RTF to HTML when it leaves the server or is received from the Internet. You can however choose to have everything sent through in it's own format but I do recommend that you keep your setting for HTML as RTF will give problems to everyone not using Outlook.

Your user must ask the sender to send their stuff using HTML instead of RTF which is the best way to deal with this.

Please let us know the version of Exchange you are on if you want to change the HTML conversion.

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Nice article but sending in Plain Text might be too drastic for most although that would solve a lot of problems :-)

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Yeah, i know. But that's Microsoft. They haven't fixed this since Outlook2000...

Here is another good article describing the problem:
Eddie_AkitaAuthor Commented:
Hello, I am using Exchange 2010 and outlook 2010. The problem is usually the signature and the attachment. I believe at one point I extended the address field numerical value at one point in Exchange and it worked for a while. The problem is that if the same email is sent to my user on their hotmail or yahoo mail it comes through signature and attachment no problem.
Some email servers understand Exchange Rich Text Format (i.e. Gmail) and some not.
Its not the address field. RTF is able to embed objects like images where as plain text and HTML is not. With HTML you can embed the image to the email an reference to this part in the html.

When you receive the dat file it is usually because the RTF email is not decoded correctly.

Eddie_AkitaAuthor Commented:
I believe so, it is only happening with one user and is usually from a person that emails her all the time, just recently it has started. It was fine when I put in our 2010 box in Dec. but as of late is when it was turning into .dat files. The client now emails both her home email and work email just to make sure it come through on one end correctly. The client says they have changed nothing in their email when sending it to us here in the office. The email that comes in has the html code for where the signature pic used to be as well.
If this is a problem from one contact only I would suggest to have the contact change format from RTF to HTML in their end (Tools->Options->Mail format in Outlook).

This should put an end to it. It will also significantly reduce the size of their emails so that might be way to pursuade them into changing format.
Eddie_AkitaAuthor Commented:
Thanks everyone, I have tried all these actions before I had come to the board and verfied them again. My next step is to contact the person's sender and see what is their settings. Thanks to all.
Eddie_AkitaAuthor Commented:
There was some good knowledge, although I don't know if there is a definitive correct answwer, this is an ongoing look into. Great responces in order to help me. Thanking the responders , Thanks
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