I got the same issue in OSX, the download button is not downloading. Just wanted to create some stats on this. Solving it per old-fasion style.
When pressing the "Download"- button in the app you have the option of canceling or open, however you cant open any file since they are all greyed out, but when pressing the open button it starts to download the file, unless you have the file in your download folder already, then it asks you if you would like to replace the old file. So it works! But the "Open"-button need to be renamed "Download".
All the best!