Having the same problems as the OP, getting that error message using either the switches or using an AutoIT script. I wouldn't post unless I wasn't having any joy as I usually get the answer from a search, and i've managed to get the rest of my unattended install working fine that way. Its just ZoneAlarm giving me gip now I'm talking about the free ZoneAlarm, and I downloaded whichever version is current as of today. This is my current switch: zlsetup.exe /s /i /noreboot I have also created and AutoIT script and tried that but I still get the error. If there's no way around it then i'll just dump the .exe to C:\ and then perform a manual install once everything else has finished.