During the Rachni Uprising of 2190, the top Citadel scientists, including Salarians, are working toward a cure for the Krogan genophage due to their agreement to cure the Krogan for their help. By the time the cure is completed and put into production, the Rachni Uprising has ended without the help of the Krogan. Because of this, the cure for the genophage was not given to the Krogan and was locked away in an undisclosed area. This angered many Krogan, though most remained apathetic.