If you haven't already done so - Send the sample/s to avast as a Undetected Malware:
Open the chest and right click in the Chest and select Add, navigate to where you have the sample and add it to the chest (see image). Once in the chest, right click on the file and select 'Submit to virus lab...' complete the form and submit, the file will be uploaded during the next update. Note: manually adding to the chest doesn't remove them from the original location, so they still have to be dealt with in that location.
Or
Send the sample to virus (at) avast (dot) com zipped and password protected with the password in email body, a link to this topic might help and undetected malware in the subject.
