InstallAware

How can I tell IA that the installation failed? (e.g. if my EditFile plugin is unable to find the file)

RunTimeExecute contains a parameter Return but the dox says "Reserved. Set to 0."

You may do this using variables to hold return values. For instance, plug-ins that install runtimes report ERROR or SUCCESS in the optional return value variables. They define an additional field for those variables.

OK, I'll add this functionality to the EditFile plugin. Thanks!