internet connectivity

Hi and thanks in advance. New Win 10 user. Avast Premium user. It appears that Avast is interfering with my internet connectivity. Randomly there is a lag in connectivity for a minute or two (sometimes longer). Happens in all browsers error message is that cannot connect to web. Once all Avast settings are disabled, there is no problem with connectivity. Thanks again for any insights.

Is this a upgrade to Windows 10 from a previous Windows version ?
What exact version of avast ?
Is there any other security (related) software installed ? (or was there)
Already performed a repair of avast ?
Already performed a clean installation of avast ?

This is a new machine that came with Win 10 loaded. Avast Pro Antivirus 12.3.2280. There are two other programs - Malwarebytes Anti Malware and Win Defender. Win Defender has been disabled. Avast and Malwarebytes were installed after getting the machine. It appears to be a new problem perhaps associated with the newest Win update. Also, since my first post, it appears though I haven’t completely confirmed that any instance of anti-virus running will create the problem. I should add that this only happens when wireless. Hardwired works fine. I have not repaired or reinstalled any of the anti-virus software. Thanks again for your help and insights.

Well, it looks like it’s not the anti-virus software after all. Thanks for your help.

Get a WiFi analyzer and choose a channel that is not (much) used in your area.
It might help.