Text in To Field whith Windows Send to Email

One of my user gets a text in the To filed of a message each time he uses the Windows Send to … Email from his Windows Desktop.

The text is actually an old phrase he used to signed his messages with.

I have checked his mail Preferences to make sure this text does not appear any more.

The template is French Mail85

How could I solve this problem ?

Thanks for your help.

Jean-Pierre