I created a new regular user with the username of Mike Perry. Installed the Site Sculptor extension -- it works. I go back to the new Michael Perry user and the SS preview doesn't work. I switch to the Admin user (administrator), and it works. I switch to another regular user and it works.
The new Michael Perry username (clean) seems to hang the extension preview.
If someone from WA wants to follow up with this I'd be happy to help. For now I'm going to transition to the new Mike Perry user for everyday use