Hi @snapmediadesign
I’ve checked both sites along with another fresh copy I installed on my localhost, here you are my result:
- This is how this line
RegExp(["[ in this file /pro/cornerstone/assets/dist-app/js/cs-vendor.js looks like on your working site:

- This is how the same line in the same file looks on my localhost “working fine by the way”:

- Now, this is how it looks like on the non working version on that other server:

and the browser is showing error on that exact line in the browser console preventing the builder from loading:

So, it’s either the file is broken, in this case try to delete the theme files and re-upload them again via FTP.
Or your web host is loading this file in such a way that makes it looks different (different encoding maybe?), in this case you need to reach out to them with all this information.
Thanks.