Today I performed a full system scan and Avast indicated that it scanned 22GB of data, but there is only 13GB of data on my harddisk. Is there something wrong with the way Avast is counting data, or does Avast extract data before scanning and counting? I am using Avast Free Antivirus 5.0.462.
Edit: The “problem” occurred on my Acer Aspire One 110, I have replaced the original hard disk (SSD) by a 30 GB HDD (MK3008GAL).
The quantity of data reported by explorer is always going to differ from what avast has scanned.
e.g. windows explorer or the drive properties, etc. only reports the physical size of the file on the HDD, when you have lots of archive files the measurement is based on the packed size of the file. When avast is going to scan an archive it has to unpack it to accurately scan the contents it records the total size of all files scanned including the archives that it has unpacked.
It also depends on the type of scan you have done, which you don’t mention.
I used the standard settings for the full system scan. I think this includes scanning (and extracting) the self-extracting DOS and win32 files, which explains the difference in amount of data scanned.