What computer are you using? Do you have any internet security on it? If it has been cleaned up previously, whoever did it should have downloaded some free security for you.
In order to see if I could reproduce your issue, I went to that website, joined (what a way to get a lot of junk email!), searched for the Turning Leaves pattern, clicked on it, and clicked on the download. It downloaded just fine. I got no warning messages at all. My computer is Windows 10 and my dh has put a *lot* of good security on it (that we pay for).
I am wondering if your computer is infected with something that is giving you this warning. You said the site wanted you to download a screen, but I saw nothing like that. I had to go through several screens when signing up and was careful not to check anything that would have resulted in marketing emails coming to me. I had to go to my email account in order to activate the site's account (they want to make sure I didn't give them a fake email). The download itself was seamless. So I'm wondering at exactly what point you got the warning.
Edit: The download is a PDF, so I think you need to have Acrobat Reader to open it. (I believe Acrobat Reader is a free download. It is software that allows you to open PDFs.)
Last edited by Prism99; 08-28-2017 at 10:31 AM.