Downloaded models do not finish installation prevent the software from being used.
Hi.
Here’s a brief statement from Topaz about this kind of problem
This can happen if antivirus, firewall, or a VPN blocks the installer from installing the files.
Disable any of the above software, then run the Topaz Gigapixel installer again which will repair your installation and add any model files which were missing.
Here’s the link to the full article about loading models
Hope this helps