Avast starting causing issues for me a while ago. Not only my DAW but my wife's work laptop. I nuked Avast and after significant research went with Webroot Secure Anywhere. http://www.webroot.com/
 
Much lighter system load. So far, it's working well.

I have built/upgraded/repaired close to 200 hundred computers over the last couple of years or so, and I always load them, and any of mine, with Avast - no issues to date, other than a single time where Avast had interfered with a download of one of the Sonar updates.
 
I have subsequently added folders related to running Sonar to the do not scan list in Avast, and have had zero issues since then, just leaving Avast running while I do whatever is needed in Sonar.
 
None of the other folks I loaded up Avast with has indicated any issues either, with Avast.
 
Bob Bone
 

Nothing on my DAW. I suspect oddities I will take it offline and give it a good cleaning.
This keeps it lean and mean.

Sometimes uninstall and reinstall (to latest) works.. as with all software that gets upgraded periodically... Sometimes the upgrades screw up.

Many Thanks to you all for these comments... Avast ran fine before I paid for it.
It's hard for me to stay on top of all studio technical information ...however, I monitor every aspect of the production machines ...this issue came about when I upgraded form free to paid ...I see good reasons why I had immediate problems in all three desktops....

Nothing had to be adjusted in the free version, other than a few minor settings ...the paid version can be configured in great detail ...again it's easy to see where it got a bit out of hand

I mention it as a potential problem with SONAR because the customer service tech stated there were "known" issues with the two co-existing on same workstation.....

There's a lot of great information here from all of you ... I hope the admins see this and make it an archive topic.... Thanks Heavens there's so many folks in this thread who are familiar and comfortably conversant with this issue!!

Best Regards and Thanks Again

Currently running the free Microsoft Security Essentials after getting BSOD when upgrading via CC and using iObit Ultimate blah blah. As Doctor says above, excluding Cakewalk is a good idea and I've not had one BSOD since using MSE.

Nothing on the DAW.
DAW goes online when I need to (a) download vendor updates or (b) reg software (if there offline reg is cumbersome). 
 
Any low price/freebie-type stuff goes via the laptop, parsed with BitDefender, then copied to the DAW.
 

never looked back leaving mcafee suite...but I feel un safe since it had a pretty good firewall
so any suggestions for firewall (win 10)?

Sorry to be controversial but anti-virus software is mostly ineffective these days. The best thing you can do is to ensure your key components are kept up to date, all the time - your browser, your operating system, Java, and Flash are the 4 big ones. The second best thing you can do is run with User Account Control ON at all times, which can often stop a virus in its tracks even if you do accidentally download it. Beyond that, the built-in Windows software such as Defender is good enough and less intrusive than 3rd party software.

gustabo
I use Avast with no issues of Sonar crashing at all. 

Same here. I've been using Avast for years ongoing with the latest version of Sonar available. No issues.