anytime a new relaese is present, nothing works!! Have you got an Q&A Team?
OK, when you set a .NET Assembly '.NET Installer class= yes' you get an error: "ISDEV : fatal error -6652: The file _isconfig.xml can not created to use with InstallUtilLib.dll."
Yes, the Installer class will run correctly with installutil.exe. Yes, the RunInstaller Attribute is set to 'true'
We've started to see a couple reports of this, but haven't been able to fully diagnose it yet. Are you building in a folder that's controlled by source control, or otherwise have a read-only project folder? If there's already an _isconfig.xml file in that folder, could you rename it and if so does that resolve the behavior?
While it's useful to resolve this problem, you might want to also consider not using Installer class custom actions and instead use the CoCreateObjectDotNet() InstallScript function to consume a ComVisible(true) class. This pattern is much more reliable and provides a much more meaningful way of passing data to and from the custom action.
