Palisade DecisionTools which includes @Risk is not supported on MacOS through our remote apps. This is a limitation of the Remote Desktop Client provided by Microsoft and not a configuration issue with DecisionTools. Users have had some success using the *Beta HTML5 Web Client if you would like to give that a try.
Instructions for using the Web Client can be found here: https://kcc.krannert.purdue.edu/Faq/Item/94