I installed Avast on a machine last month. I have a similar problem, once a week, when my Yosemite tape software runs the weekly complete drive backup. Daily incremental backups do not produce this problem, at least so far.
Problem description: A program is attempting to modify an avast! INI file, possibly changing some of its system-wide settings ... Do you want to continue?
If I click on yes, the backup continues correctly. It is annoying because I need to be there. Otherwise, the backup will not continue.
Is there a workaround without affecting security?
I am running Avast! version 4.8 Professional, build April 2008, 4.8.1169, Xtreme toolkit 1.9.4.0, Active Skin 4.2.7.3, file version 080411-0.
Thanks for your help.