Running a Imac with Sierra ver 10.12.1. In the past 14 days apparently I have consumed over 200 Gig of Data. Today between 7:45 A.M. and 1:00 PM I consumed 32 Gig. Ten days ago when I was informed of my data usage by my provider; I changed my passwords on both my modem and my computer; assuming that someone in the neighbourhood was the culprit. Nada. The data usage didn't stop. Today; I checked my activity monitor and noticed that "com.avast.proxy" had uploaded 29 gig of data. What is with this? Is it a bug; or is it something on my end! I have since removed Avast from my computer! I'm now using McAfee as my anti virus program.