i tried to download mapleroyals through the website download and after downloading the setup and install it, it then receive a message that the file has virus/error.
Your anti virus or firewall is most likely blocking it. It's not a virus, it just seems to not like .exe files very much.
i tried to allow mapleroyals on the firewall but it still didnt work - my anti-virus deleted the file right after it finishes installing.
I assume you fixed this issue then? disable anti virus until you finished installing it, then turn it back on.