http://steamcommunity.com/app/306130/discussions/0/1488866813759728329/?ctp=2
The above link provides steps to work around the additional 87GB that the launcher asks for after you've completed the initial 80GB download from Steam.
You don't have to watch the video, just read what the guy who posted it says in the description in the thread.
I just bumped the post because it worked for me 5 minutes ago
Cheers!