for some reason my avast can not connect to server when trying to update…no idea why…thanks in advance
I think you need to ad some info…so we don`t have to guess…
What OS…XP/vista/W7…32/64 bit…
What avast…4.8 or 5.0 pro / internet security…
Do you have a firewall ?..what…
been like this for a long time…or just happend after an update ?
have you tried avast repair ?
For a repair of avast. Windows, Add Remove programs, select ‘avast! Anti-Virus,’ click the Change/Remove button from the pop-up window, scroll down to Repair, click next and follow.
Hello,
Me too… I have two boxes, One using Windows 7 , the other uses Windows XP Pro SP3 with latest Avast 5 free version too.
On both machines I use Comodo with Defense + as Firewall.
On the Windows 7 machine Updates went fine.
On the Windows XP connected to the same router, Avast refuse to update. I use standard settings. If I do manual Update, updater works fine. I tried a repair, no luck.
I have completely un-installed Avast 5, cleaned the registry, rebooted, installed from scratch but no more luck. There is no error into the Windows Event viewer and Avast has full permissions to connect to the Internet into Comodo Firewall.
I must say I am lost after 15 days trying to get Avast 5 updating defs itself.
Never had such a problem with the 4.8 version.
Any help will be appreciated. 
- Sorry if my English is not clear - Not my native language…
What happens if you remove the comodo firewall ?
I uninstall Avast and then reinstall it ,the updating is finally ok .
Removing Comodo makes Avast automatic update working. Thanks
Comodo switched off before, Just the manual updates were working. The firewall was blocking ICMP type 8 (Echo Request) and Avast need Echo Request (Ping) in order to use Automatic updater. I think this not normal and a little bit scary.