"License file not found."
Mathcad 15 reached its official end-of-sale on December 31, 2021 mathcad 15 install download
Since Mathcad 15 is a legacy version, you can typically only access the installer through the following official channels if you already have a license: PTC eSupport Portal "License file not found
PTC occasionally provides trial installers for historical reference. A Google search for Mathcad 15 M020 download PTC community may yield a sticky post with a direct FTP link. : Only use links from official PTC domains ( ptc.com ). mathcad 15 install download
Alternatively, see this PTC Community thread for alternative links. Step 2: Install Mathcad 15