I have StruCAD V15.1 on my system but lost my license when I did not switch to Tekla. Can I still use it somehow?
StruCAD application is no longer supported which means you won't have the possibility to use it. I have tried to find a way to overcome the issue in your question, but reached a page that says StruCAD is discontinued and no longer supported.
Official page: http://www.tekla.com/uk/strucad-struengineer/download.html