I upgraded Photo AI to version 1.4.2 running on an iMac Pro running 13.4.1. Whether used as a plugin in Adobe Photoshop or Lightroom Classic or as a stand alone app, the program stops processing and gets stuck in Idle with every image I load in.
I had a similar problem which was solved by downloading a fresh installer, replacing version updated from within the app. Instructions included providing some accessibility access that I wasn’t able to do, but the new install worked anyway.
I’m keeping an eye on this so please update us if you are still having issues and I can get further information.
If it’s not working after reinstall, open Topaz Photo AI, go to the menu bar on the top and click the Help > Open Log Folder menu option. Upload the log files here (especially most recent ones at the bottom).