So, I have a Win 10 Pro OS, and Avast Free Antivirus. Turbo Tax 2017 Deluxe DVD installation will not install because Avast is blocking it. Why? For those having the same issue, you need to go into Task Manager, and stop Avast in the services tab. Install Turbo Tax 2017, then restart Avast. ASAIK, there is no good reason for this to be required but it is.