Avast 8 Compatibility Install?

How should I configure avast 8 free to run with another Security software as in Norton 360? I have N360 installed, because it was 20 dollars for a years subscription yesterday on Amazon. I remember avast 7 offered a compatibility install mode which made it a second line of defense. It worked with other Internet Security suites. I would like to know what I need to do exactly to get Avast 8 to work with Norton.

Uninstall Norton completely with its utility tool. Never ever run 2 AV at the same time. It will create problems in your sys and weaker to malicious attacks.

BTW welcome to Avast! forums.

Why would avast offer a compatibility mode then?

It was dropped on version 8.

There are other options. You can try Avast! and Malwarebytes´ for add on protection and second opinion scanner.