This solution especially applies to mozilla firefox. Go to search, type cmd, and open command prompt as administrator (right-click open as administrator). If youre having trouble accessing command prompt as an admin, then you better take a closer look on this guide. However, if sfc fails, you can always turn to dism. Same goes for windows built-in firewall.Having bought a subscription, you can download this or other directories on our website. To download the file, click on the button below.