I'm propably a bit late, but just a heads up to anyone who wants to downlaod JDownloader. I suggest looking for an adware free version on their forums. The regular downloader comes with some crap that installs automatically without your permission. I think (or rather, hope) that it doesn't fuck up your PC (I downloaded it the regular way as well) but it's better to be safe than sorry.
This is the post that links to the adfree version: https://board.jdownloader.org/showthread.php?t=54725
Is there any proof for your statement "The regular downloader comes with some crap that installs automatically without your permission"
From your own link I can read the dev say...
"The installers on the main page asks you if you want to install a bundled software - for example a toolbar. This is the way we earn money. The installer shows you a screen, and you can uncheck the toolbar installation. So you you read the installer screens, you will not get anything unwanted installed."
I never know about adware free version but mine are regular one and it safe
I know this for sure because I'm using 10 pro with "Allow apps from the store only" option enabled which will notify me if anything (backgound or not) try to install to Windows
With "Allow apps from the store only" enabled I can't install anything even if I want to