Data Tested greater than data on drive

Avast Free Antivirus / Premium Security
1

Using Avast Pro 5.0.677 to run a full scan of drive C: on a Win XP SP3 system, Avast reported that 26.4GB of data was tested. When I open Windows Explorer, right click on drive C: and choose Properties, Windows reports that 19,331,895,296 bytes (18.0GB) are used.

Why is there such a significant difference?

2

Because avast! unpacks quite a few archive formats - and the unpacked (and scanned) content is also included in the statistics.

3

Igor,
Thank you for the explanation.