You can either pause or Stop providers, right click the avast 'a' icon and select those you wish to pause/stop, stop is probably the better option, answer No to the persistence question or it won't start next boot.
To restart these providers, left click the avast 'a' icon, this will display the avast on-access control, select the provider you want to start and click the start button.
Whilst running other security scans like SAS I would suggest you pause the standard shield provider.