For prerequisites the logging will depend on the package you are installing. For msi based installers you could include the /l*vC:\Temp\MyInstall.log For setup.exe based setups you will need to consult the documentation for the company providing the installer. For instance, I do not think there is a way to specify the log location of the .NET installers, but it will create logs in the users %temp% directory.
I do not think there is a way to specify logging ONLY in a failure event. Logging is either on or off.
Any other type of behavior would require you to include your own bootstrapper and control the logging from the bootstrapper.
Thanks for the information. You have confirmed what I have been able to get from the documentation and some support interaction. In my case I have been able to turn on the MSI logging on the general tab, but get the prerequisites logged you have to use the /debuglog command line. Unfortunately, this has a side effect that if you have to reboot during the prerequisites, the installation does not restart upon reboot even though the prq is set to restart after reboot. Looking through the command line parameters I have not found one that will force the reboot.
