Faced such a problem, when downloading an update from GOG Galaxy (16 GB), the speed drops by 57% to 0.1 MB / s and the size of the downloaded update from 9 GB / 16 GB becomes 16 GB / 16 GB, and this message gets out by 59% : GOG Galaxy Crash Reporter after which the client closes... Restarting GOG Galaxy, or downloading the update again does not help :( Maybe this is due to the fact that the game client and the game itself are on different discs? (HDD and SSD)