I have built an InfoPath form and web enabled it. Users fill in the form in Internet Explorer and attach a file to it. When they press the “Save” button, a mail is sent to some receivers in Outlook. When they try to open the form, they get the following error:
After I press OK on the error message the form opens up as a normal mail, and not in InfoPath as expected:
The attachment is removed, because if I try to open the attached form.xml file I get the same error in InfoPath.
This happens to ALL types of files, except .txt files. If the user attach a .txt file and the form is opened in Outlook, it opens correctly and you can see that attached file: