I got the following message on update from Sygate firewall
Trojan horse “IntrusePack 1.27b” detected in C:\Program Files\Alwil Software\Avast4\Setup\avast.setup, process id: 4294355977
Description:
Process has been terminated.
Allow avast.setup into Sygate firewall.
It’s a well-known bug (or compatibility problem) of Sygate that has been discussed a lot in the past.
avast.setup is a temporary file (created from setup.ovr) that is used to update avast through Internet. 