The software doesn't appear to support Windows 8.1 64bit because the development is uncertain. I have checked the official website, and the only thing I could find is related to SEO which is something totally different than what IconScanner does. You might need to use other icon applications. Use the database of Software Informer to pick something else for your needs: http://software.informer.com/search/icons
Note: IconPackage is a good application that can be used for icon operations.