I'm having the exact same issue, where my download got stuck at 22%... I'm downloading it to a 2 TB My Book Essential external drive , thru a Ubuntu VM with 3gb ram and 2 processors set aside for it. Also I got to 22% because i had a consistent 8 connection download, now its steady between 1 -3 connections and the download is very slow to the point of years.

Any ideas on what I should do?