I've been messing with Mathcad 13 for a while and have this odd problem.
If I use the msi to install it rather than their setup, the
application will install if I set the User Interface Level to reduced or
full. If I set it to anything else, it will appear to install, and then
run and complain about missing files (help files, templates, etc)... And
it's missing thousands of files. Very strange.