If Avast blocks an application, you can exclude it from Avast scans by going to Settings > Exception :
To exclude an executable file: *example.exe
To exclude the entire path to an application: C:Program FilesAVAST SoftwareAvast*
To exclude all files from an application: *AVAST Software*
If Avast blocks a URL or a web application, you can exclude it from Avast scans by going to Settings > Exclusions:
A subdomain: https://translate.google.fr/*
A comprehensive range: *.google.fr/*
A web page: www.google.fr/*