Avast Anti-Virus Turned On but Action Center doesn't Detect after August patch t

Avast Free Antivirus / Premium Security
1

The subject says it all.

The action centre asks me to activate an antispyware/antivirus app even if Avast is full working.

This started popping up after the August’s security update.

Windows 8.1, 64 bit, Italian localization.

2

→ http://www.avast.com/it-it/faq.php?article=AVKB81#artTitle