From: 27th Penal Battalion
I turned the computer off for at least fifteen minutes and rebooted. Same result. I tried disabling the firewall, but got the same result.
Edit: The above results were for the launch icon in my CS folder. I then went into a subfolder -- a separate Unit Viewer folder, within which was another launch icon, and I used that one, and it worked for all three (EF, WF, and RS). I'm thinking the launch icon in the CS folder was for the earlier version of the Unit Viewer, which was why it didn't work.
it is strange, there were no changes in 'Play Game' button functionality
check if there is settings.txt file next to JTCS_UnitViewer.exe
If yes, delete it, maybe there is a wrong path stored for game directory