I have a series of InfoPath form libraries. All three libraries use InfoPath Client forms - the forms contain parameterized queries so they can't be converted to broswer-based forms. The problem is that some users can successfully open, edit and save their InfoPath forms to the library, but others are having issues when trying to save the form - the form saves as an .XML document which is then unreadable. Has anyone else seen this behavior and do you have any diagnosis for it? In some cases I have gotten feedback from some users that they got the "Before opening files from this location, you must first add the web site to your trusted sites list..." error, but I do not have confirmation that this is happening in each case. I cannot duplicate the error myself, but I access the system as a site collection admin.