I have set-up an Avast account with a validated login and password (I have logged in to my account online, so I know it works). However, the Avast app on my Mac will not let me sign-in using the login email address (see screen shot). I think it may not like the plus sign in the Gmail address but that is how I keep track of registrations like this so I need to use it. Plus it has already been validated so it should be acceptable. I only have 7 days left to register.
Avast for Mac version 8.0
Mac OS 10.8.5