File shild question?

[REDACTED]

I have lg G3 and installed avast mobile security.I am very pleased with this product but have some questions which helps me to understand him much better.
1.In file shild there is otion ''scan files when reading''-can some1 explain me what that do? and is it good to turn it on?
2.I have mcafee mobile security installed on my lg ( i got it with phone,cant uninstall(except root and that)).I clear account form it,and that stop it to run in background.Disable his administrators function too.
So will it had some interferance with avast?
3.Does avast mobile security scan mozzila for android.(wasnt see mozzila in web shild info).

ALL THE BEST

[limojoe]

Hello,
1) In the case that your filesystem was already scanned and you will not change sdcard, there is no extra need for this.
2) I do not expect any extra interference, only a little bit slower performance of the phone. 
3) We do not scan mozzila at the moment.