The normal "setup.exe" install failed when attempting to install Mathcad on a brand new Windows 10 machine. I had to engage tech support in a lengthy session, in which they had to download a Microsoft C++ file and make edits to the registry, just to get it installed. Apparently newer versions of Windows 10 use a C++ file that is not recognized by Mathcad 15. This is totally unacceptable!! PTC is doing an abysmal job of maintaining this software, apparently because they've bet the farm on Prime, which remains plagued with numerous problems. I'm about ready to give up and use MATLAB, or worse yet, just go directly to Python.