Usually when an another race's ship appears the game gets stuck. It normal happens when I zooming in and out or moving around the map. The music keeps playing and when I press buttons on the UI it makes a sound, but nothing changes on the screen. It seems like there's something active, but the screen is not showing it.
I have 16GB of RAM. Intel Core i7-4558U 2.8GHZ, and Windows 8.1