File sizes: Avast scans more data than the file has???

[Marcgal]

Ok. So I downloaded a Wesnoth installer (http://en.wikipedia.org/wiki/The_Battle_for_Wesnoth) and scanned it by Avast Free. Windows tells me that the installer has only 298 MB, and when I tried unpacking it with 7zip it had over 400 MB. But Avast told me that it scanned over 700 MB! That's a nonsense! Also, if I'm not mistaken, after I scanned the whole HDD Avast claimed that it had scanned more data then my HDD can store - I usually have ~30-40GB stored on my Windows partition (there's also a Linux one, because I tried experimenting with it a few months ago), and it can store up to 45.4GB, but, if I rember well, Avast claimed that it had scanned around 60 or even 70 GB! I'm totally confused with it.

Sorry for my English and thank you in advance.

[RejZoR]

It reports the size of all the unpacked data. Even stuff that's packed with compressors no archiver can ever unpack. These days almost all executables are packed to decrease size.