I am not sure exactly when this started, but one of the updates a few months ago began blocking my DVR's. It has taken me months to figure out what the problem was. I have security cameras on my income property and another home in other states. The tech people that installed one of the security cameras eventually replaced the whole system, but to no avale. In desperation, I disabled Avast, and "pow", there were my cameras. A little pokeing around in Avast, and found that if I turned off the web shield, my cameras worked fine. Another computer in my home (they all run win 7) has never had a problem, but it has an older version on avast, and works just fine. So, if anybody has DVR's, be aware.
Now, Avast, how do I get the Web Shield to work and still have access to my cameras???
