If your system is having genuine windows operating system windows 7 or later, and if your system is trying to install Windows anniversary update , and if it is getting failed. This is happening because ,you have activated 3rd party Antivirus application installed in your system, and that is causing issue. Please remove any existing 3rd party antivirus or security from your system, reboot the system, activate built in windows defender, it will protect your system without hassle,don't worry.
One more option is to use windows 10 media creation tool, when asked instead of install select option to create media iso dvd, then upgrade from that dvd, In that case , you will be able to install anniversary update for windows 10. Make sure you disable your antivirus from services.msc
