If you have a previous version installed (as I did from a previous SOS giveaway), you should uninstall it before installing this version.
I did not (I thought it would just update in place), and all sorts of very weird things happened necessitating a hard reboot after the installation failed to close some files it needed to close, and also messed up the installed older version where it would no longer load.
The publisher should be more clear about that requirement – uninstall older version, install newer version.