XML files do not open
I am posting this question again. I created several Mathcad files (using 15) last year. I tried to open them yesterday. I got a message saying "not a valid XML file" . Then I tried to attach the offending file and it would not attach, saying "file contents do no match file type". Can someone out there explain what is going on and how to correct this. Has PTC developed a fix for the problem? My email address is dmgjr@suddenlink.net

