This is a strange problem that I have never seen before. I have two machines, both running Win 7 and running the latest version of Avast, both seem to be downloading large amounts of data. I noticed it when we were using more data for our monthly limit then normal, 2gb+ in a couple of days when really only browsing.
I installed NetLimiter and let it run for couple of hours and this is the result for the avast! Service (c:\program files\alwil software\avast5\avastsvc.exe ).
The other computer downloaded twice as much data in the same amount of time.
Both installs of avast have their automatic updates (turned off at 4:00pm), for both program and definitions.
Does anyone know what might be going on here.