Delay Auto-Update check:
You need to edit (using notepad) avast5.ini the [InetWD] section of the C:\Documents and Settings\All Users\Application Data\Alwil Software\Avast5\avast5.ini (XP file location). Location for Vista, win7, C:\ProgramData\Alwil Software\Avast5\avast5.ini.
If you did a clean install of avast6 the folder names are slightly different, \Avast Software\Avast\ instead of \Alwil Software\Avast5\ other than that it is the same procedure.

  • Broadband connections, add this line:
    AlwaysConnectedWaitSeconds=120 and
    AssumeAlwaysConnected=1 if not present (or edit AssumeAlwaysConnected=0 to AssumeAlwaysConnected=1)
[InetWD] AssumeAlwaysConnected=1 AlwaysConnectedWaitSeconds=120
When complete save the changes, avast's self-defence module will ask for confirmation, etc. answer Yes.

The figure is seconds and the above equates to two minutes, you could try that and adjust upwards if required, 180, 240, etc.