Okay, so apparently GS needs to update categories periodically. That is fine but it shouldn’t render the program useless if you are offline. Connecting to a hotspot did not solve the problem.
The program had been open for several days but my computer closed overnight. I opened the computer to work and GS was stuck generating preview. I waited for 40 minutes for it to resolve, re-booting the computer in the meantime.
To fix I had to close the program, connect to hotspot, then re-open GS. Connecting to WiFi without closing the program first did not work. Afterward it updated the categories and the preview pane opened. This should not have been necessary and a loss of 9 hours of potential work time. It should detect there is no connection and carry on. Sometimes there is no internet, like while stuck in your car waiting for hours but can’t get out just in case, because the broken ferry may be ready at any minute…
Okay rant over, but that sucked.