Are you surprised to get hit when you walk across a 4 lane highway, the same is true of cracks and keygens.
Looking for cracks and keygens is a very high risk activity, aside from any legal/moral issue.
The only way they can detect is by analysis and they need samples to do that.
Send the sample to
virus@avast.com zipped and password protected with the password in email body, a link to this topic might help and false positive/undetected malware in the subject.
Or you can also add the file to the User Files (File, Add) section of the avast chest (if it isn't already in the chest) where it can do no harm and send it from there.
A copy of the file/s will remain in the original location, so you will need to take further action and can remove/rename that.
Send it from the User Files section of the chest (select the file, right click, email to Alwil Software). It will be uploaded (not actually emailed) to avast when the next avast auto (or manual) update is done.
You could also check the offending/suspect file at:
VirusTotal - Multi engine on-line virus scanner and
report the findings here the URL in the Address bar of the VT results page.