Windows 10 is less susceptible to trojans, viruses, and malware than any other previous Windows version and it is less prone to attacks than Apple OSs. This is mostly due to the fact that they don't give users the option of installing upgrades and patches any longer, they force it on you and most of the time you don't even know it is happening, your internet connection slows down and so does your pc. Sometimes it makes you reboot which makes things worse because it forces Windows to start the download process from the beginning. I have learned to check my system settings on a regular basis and check my update history. The first Tuesday of the Month is called Big Patch Tuesday by most pc techs because that is when MS sends out its biggest update which is usually an upgrade of the whole OS. Updates to programs such as Windows Defender can take place anytime.