Reading the several comments on this subject has not led to a solution. The Firefox Setup 81 and Installer are sitting in the downloads file, but when I click either "Open" or "Run as Administrator" I get a Windows "For security and performance Windows 10 in S mode...." followed by two options "Learn more" or "Switch out of S mode". When I choose the latter the "Switch out of S mode" page arrives. Now what? Thanks.