I am currently using Avast with no problems, but I am still curious.
Does Avast sometimes make mistakes, like deleting important system files that don’t contain malware?
I hope someone can answer this.
First - Avast has a very low FP rate, as seen in many of the various testing labs publicly available results. These test results are frequently posted in the avast forums.
Second - System files should be digitally signed, if so and they aren’t tampered (signature is valid) with then it shouldn’t even be considered infected.
Third - There is nothing to stop you adjusting the Avast Settings (though you don’t say what Avast program you are using) to stop autonomous action in the Avast Shields. I never allow any program to take autonomous action, I make the decisions for my system, so I set it to Ask. Obviously you have to have some knowledge to make the decision.
I have only been using Avast for over 17 years and have not experienced a false positive on a system file.