Avast somewhat randomly blocking DNS requests

Avast Free Antivirus / Premium Security
1

For a month or so now I’ve been having problems with a Windows 10 computer randomly, sometime about mid day, losing internet access. Usually, after a few hours of frustrating rebooting the PC, the router, the modem and doing everything I can think of, it randomly starts working again.

I’ve diagnosed, tracked, traced and fiddled with it every time it happens. I tried different routers, I even bought a new Netgear router. I’ve talked to my ISP. Nothing.

When the problem occurs, everything else on my network keeps working. Just my PC. So I know it’s in the PC. But, everything at the IP level seems to work. I can ping the router. Through the router and even through to the outside world. I finally tracked it down to DNS not responding to requests.

Finally, today when the problem happened, it occurred to me to disable Avast, so I right clicked on the Avast icon, went to Avast Shield control and disabled them all for 10 minutes. I instantly had DNS access again. I had an NSLOOKUP instance running and connected to 8.8.8.8. And, my browser started working immediately also.

I turned all the shields back on and everything kept working. I’ll have to wait for tomorrow (or the next day’s) random failure to test it again.

Windows 10 Home 64-bit Version 1809 Build 17763.437
HP Notebook - 17-by0062cl
Avast Free Antivirus 19.4.2374 (build 19.4.4318.460)

It was happening on an earlier build also. I know it’s updated at least once or twice since this problem started.

2

Follow instructions: https://support.avast.com/article/33/ and post your File-ID here afterwards.

3

File ID is 2VF8E

I got a message about incompatible software, but it didn’t tell me what. A link took me to an article with a list of other virus software, I scanned down through the list and I have none of them installed.

4
  • Other security related software installed…?
  • Which AV(s) did you use before Avast…?
5

This computer is new. It’s only had Avast on it. I also use MalwareBytes, but it wasn’t on the list I saw.

This is the link I get from the Service Tool when it fails the “Compatibility Test”.

https://support.avast.com/en-ww/article/11/#articleContent

6

Regarding Avast & Malwarebytes, see: https://forums.malwarebytes.com/topic/200324-exclusions-for-avast-users/

7

OK. I added all those exceptions. We’ll see what happens.

8

Is the HDD working hard when DNS blocking happens? Some users (including me) encounter similar issue when HDD activity is high.

9

No. No excessive disk or processor activity.