Windows Defender vs. Alternatives

I've been using the Microsoft Defender or earlier Microsoft Security essentials since Vista days.  I had been using 3rd party AV but was having problems in Sonar/Vista  Sonar support advised some 3rd party AV's could affect Sonar.  I switched to the Microsoft and my problem went away.  I also use Malwarebytes (paid version). 

Defender here.. since Windows 7 (skipped 8), running 10 now.

I used Avast for years and then switched to Defender because I find it totally adequate. If you're worried about it interfering with your music production then just add all of your related music folders (Cakewalk, VST's, sample libraries etc) to its exception list.

tlw
Compared to most third-party offerings Windows Defender is pretty light on the system and relatively (very) unobtrusive.

That's why I finally stopped paying for annual updates for 3rd party solutions (Trend Micro for years, and then Kaspersky for years; Norton/Semantec is worse than any malware or virus you'll ever get).
 
I still run an ad blocker though (Adguard). It works well and doesn't seem to cause any issues with SONAR.

Rob[atSound-Rehab]
 
Thinking about replacing it with some free antivirus, which is less intrusive (e.g. Avira AntiVirus) - thoughts, suggestions?

I have had good luck with Avira Free, and it has the same detection methods as the Pro version.  So unless you want additional mail protection or web scanning, no need for Pro.  It has a good file exclusion feature, so I just put all of my music programs and data folders in there and I'm good to go.
 
From what I've read over at AV Comparatives, https://www.av-comparatives.org/comparatives-reviews/ the consistently top three AV's today with the best detection and the lowest false positives are Avira, Bitdefender, and Kaspersky.  The first two offer free versions.  I run Bitdefender Free 2016 on my home theater PC, but it has no exclusion settings.  But there is a one-click option to turn on/off active protection.  I leave it off unless I happen to be using the web browser or downloading something.  Very light that way

soens
There are sites that report regularly on how well the AV contenders are doing. I'd check them out, tho I will say that Norton is always near the top.
 
People are always trashing Norton but I've used it for almost 20 years without any issues. As long as I have a Windows 7 system I'll keep it around. But my Windows 10 system will doubtfully ever see it.

That's all well and good, except that the OP requested some free solutions advice
 

soens
 
And if you think your AV is messing with your DAW, simply turn it and the WiFi off while you work offline.

 
Best suggestion!

Zero issues using Defender for years.  I stay away from pRon sites as an added measure of safety 

soens
Personally, if you want free AV then Defender is probably as good as any of them. But they will all be listed near the bottom of any list for reliability. You get what you pay for.

Actually, Avira is as good as any paid AV.  Avira Free uses the same malware detection engine with Avira Protection Cloud as the Pro version. Usually scores at, or near 100% sample malware detection rate.  Good enough for me
 
The paid Avira Pro version just adds extra web scanning and mail protection, but no better detection.  It just protects you more if you're careless about what you click on, or open emails from unknown source.