I've installed Dropbox App onto my Windows 10 Home but cannot sign in because of this Not Supported Error. I'm not running is S Mode and have plenty of spare HD space and other settings, there should be no reason why I can't run Dropbox.
Would you mind sending me a screenshot of the error dialog box that you're seeing? If you see a blue hyperlink within the error too, please click the link and copy +paste the contents in your reply too.
Also, can you just confirm for me that you downloaded the desktop app from the website directly?