Online Armor has a web shield and program guard. Do these or any part of OA cause conflicts? I 99.99% sure I know the answer. I’m pretty sure that these protect their respective components from any outside altering.
Thus…a firewall. 
You might want to put OA on learning mode for a few weeks prior to the installation to avast! Also you will want to add avast! in the trusted processes lists. with that said and done you should be ok.
Please report back to this thread if you are receiving any problems. 
Most add the Avast! folder to the OA exclusions. Some also exculde OA from Avast!, but I haven’t need to do that.
Uh…putting off installation of avast is dangerous at best. I would rather put OA Free on learning mode than be without avast. I have had avast for over a year now and will not surf without it.
If you feel you want to add the exclusions the best way to exclude both OA and Avast is the following:
To exclude OA in Avast:
· Settings > Exclusions > Add > search for Online Armor and click on the box to the left of it and add it, then click OK.
· Real Time Shields > Expert Settings > Trusted Processes > Add > search for Online Armor and click on the box to the left of it and add it, then click OK.
· Behavior Shield > Expert Settings > Trusted Processes > Add > search for Online Armor and click on the box to the left of it and add it, then click OK. Also change action to take in Behavior Shield to “Ask.”
To exclude Avast in OA:
· Open the OA GUI > Options > Exclusions > Add > click on the pop-up window and find C:\Program Files\Avast Software.
· When you reboot OA (to go into Learning Mode), make sure ALL Avast shields are left on.
· Reboot your machine again; OA requires two boots. After this second reboot, you may get a pop-up asking you if you trust Avast. Answer the pop-up as “Trust Always” and “Remember My Decision” and you should not get any more pop-ups.
· Open the OA GUI > Programs > untick “Hide Trusted” so that you can see everything > look to make sure everything from Avast is not “blocked” (red) or “ask” (yellow). If it is, right-click the item and change it to “Trust.” Reboot.
I don’t seem to be having any issues with avast or OA Free. I must be getting good or lucky. Online Armor and avast seem to play well with each other. I am so glad OA has a “learning mode” it makes it so user friendly. Just like the best av on the planet…avast!
Enough said!