Application considered like a "Win32:Malware-gen"

Hello,

We have in my company an application which is considered like a “Win32:Malware-gen”. This application was safe until the update of 1st October.

I scanned the .exe with www.virustotal.com and only avast detect something. It’s a very big problem because all the production of our customers is down.
I think it’s a false positive detection, how can we fix this problem?

Thx.

send sample to virus@avast.com in a password protected zip.file with subject " False Positive " and write the password in the mail so they can open it

Done thx a lot