For a number of years, I configured IE to use an automatic configuration script (Internet Options -> Connections -> LAN Settings / Use automatic configuration script). Since upgrading to avast! Pro 2014, IE crashes consistently on startup. Disabling avast! shields or turning off the IE avast! plug-in does not resolve the problem. Pointing to a non-existent configuration script or switching to static proxy configuration 'solves' the problem. Turning off the automatic configuration script through Control Panel -> Internet Options allows IE to start but enabling the automatic configuration script from within IE causes IE to fail even before exiting from Internet Options.
I thought IE10 might have become corrupted and installed the IE11 Preview without changing the symptoms. I doubt the problem is related to the proxy.pac file itself - even a minimal file such as the following fails:
function FindProxyForURL(url, host)
{
return "DIRECT";
}
Removing avast! solves the problem. It re-occurs with both the free and Pro versions of avast! 2014. If IE is running with the automatic configuration script enabled while avast! is installed, IE continues to work fine, although I have not used it in this state for an extended period of time. Closing and opening IE results in a crash.
I reverted to avast! 8.0.1489 last night and the problem is gone. If anyone else is seeing this problem, please let me know to help demonstrate that this is not due to something unique on my laptop (Win7 Pro, 64-bit, latest maintenance, Windows Defender disabled, no other antivirus/malware/spyware software).
Thanks, Norbert