DavidR
6
Selecting no action only does that, take none of the possible actions. This will/should leave the file in place, but what it won’t let you do is run it. After a reboot if you tried to run it again you would get the alert again.
For many years avast has taken the decision not to have a single click option to ignore/exclude/allow to run for obvious reasons. If it was a good detection, then a single click (accidental or otherwise) could have serious consequences, for the user who might just blame avast for it.
I don’t know if the DeepScreen popup is specifically branded as such. But if I recall it does say it is running a DeepScreen check and it may take a few seconds.