I'm still running Windows 8.1 Pro and Firefox ESR is my default (& only other) installed browser. Internet Explorer Version 11.0.9600.20139 is still installed and tightly integrated in this version of Windows. Various application code seems to call Internet Explorer, creating a slew of cookies and temporary files, particularly during such operations as installing updates. Other code (such as "view this email in browser") ONLY works with Internet Explorer because it uses *.mht temporary space that Firefox is not permitted to access. Is there a way configure the system for many of these tasks so that Firefox is called instead? Or is this one of those "don't go there" ideas that only SEEMS like it would enhance security, but would really break the smooth running of my PC? Thanks!