Do not support the overall scan

I used Norton, AVG, Dr.Web, and they can do a full scan. avast! can not conduct a full scan, only scan users to install third-party software, this will lead to the the unofficial android system the virus unable to detect.Although its function is the most complete.

Do you mean the system partition?

What do you mean a “full scan” please?

YES,system partition.
I hope avast! Can like Norton, Kaspersky, Dr.Web as to scan any position, but not limited to party software installed by the user.
I used many security software, avast among the most complete, and is free of charge, so I want it to be able to do better.

System partition is scanned too, but depends on filesystem. In most cases there is no reason to scan it, because is read only and to remount it you need to have device rooted.