False positives are really only a problem if you take detections at face value and worse still delete detections. avast is no different to other AVs they all suffer to some degree from FPs. The ability to send detections to the avast chest where they can do no harm and gives options to restore a file if having moved it to the chest it has an adverse impact.

Deletion isn’t really a good first option (you have none left), ‘first do no harm’ don’t delete, send virus to the chest and investigate, google the file name, scan with multi engine scanner, etc.

You could also check the offending/suspect file at: VirusTotal - Multi engine on-line virus scanner I feel virustotal is the better option as it uses the windows version of avast (more packers supported) and there are currently 32 different scanners.
Or Jotti - Multi engine on-line virus scanner if any other scanners here detect them it is less likely to be a false positive. Whichever scanner you use, you can’t do this with the file in the chest, you will need to move it out.