dude...seriously..not that I want to excuse their incompetence, but just use galaxy..it is a good clean client and for games that get updated often, it is convenient and time saving.
Galaxy is an utter turd in my experience, failing to update games and corrupting installations.
I used it for a short while when I was playing PoE. Each and every attempt to automatically patch the game ended with me having to manually uninstall, and then reinstall through Galaxy's "automated", read "completely opaque" process, which shows you neither how much it's downloading, nor how fast, nor even what percentage it has completed. All it showed me was a loading bar, because some idiot designer saw this on his iPhone and thought this was brilliant UI design.
Another game I used it for was Witcher 3, where it famously broke the installation of DLC if your game's language audio was not set to English. I had mute characters in HoS until I installed manually, because GOG wasn't installing the DLC and then the language pack in the right order.
Fuck Galaxy, and fuck spyware clients.