After the first online installation, the first play, and the first PC rebot (all of them went smooth), the game disappeared from GOG galaxy, while the .exe disappeared totally from the computer.
I've tried to make Galaxy read the game folder (which was still there, with no .exe), correcting the problem. The platform got stuck at 0% for a while, giving me back an "impossible to write in this folder because is protected" message. I've tried to uninstall/reinstall galaxy, and to install the game by downloading the installer first. It worked after the 3rd game install/uninstall, changing the installation folder, at the end. But again, after rebooting the pc, the .exe vanished, and the game has disappeared again from the Galaxy platform. any suggestion?