In such cases, you need to disable your antivirus protection for a while. Sometimes your antivirus detects the changes which are being made by an unknown application while installing as false positives. They also sometimes block your favorite website or application. There comes a time when you need to install a new software or a driver, and your antivirus keeps stopping their installation. Why Should You Disable Avast Temporarily?
Disable Individual Avast Antivirus Shields in Windows Disable Complete Avast Security on Windows