1. What version of Mathcad are you using?2. For Mathcad Prime try the following tips: "Error "Mathcad application has stopped working" when launching Mathcad Prime x64-Bit version": https://community.ptc.com/t5/PTC-Mathcad-Installation/Error-quot-Mathcad-application-has-stopped-working-quot-when/m-p/706420#M23 "Mathcad Prime does not launch after the initial splash on Windows OS": https://community.ptc.com/t5/PTC-Mathcad-Installation/Mathcad-Prime-does-not-launch-after-the-initial-splash-on/m-p/729884#M587