WTF, seriously??? I have to completely redo the DL after 6 f*cking hours???? What kind of shite is this? The program should be able to recognize the portion already DL'd shouldn't it?

check your HD space

2.5 TBytes free, do not think that's the issue...

Are you using Galaxy? I've heard it's not quite working entirely, you might end up having to use say the GoGDownloader to get the game.

Use the browser download, goto account, select game, download each part of the game. Not sure if they implemented the download compressed installers in Galaxy yet, but browser download definately does, so that should be a smaller download.