InstallAware

When an older install already exists and we want to install a new version of our software, InstallAwares (windows installer api?) default behavior seems to be to force an uninstall of the old installation before proceeding.

Is there anyway to not have this behavior? We want the old installation to remain and have newer files simply overwrite the older. We want this because of user-edited ini-files that should usually remain untouched.
we can't use "Newer overwrite" since on rare occasions they should be replaced. Historically (ie. not InstallAware) we have used doctored created/modified dates to determine if to replace a file or not.

Our own attempts to remove the uninstallation have only resulted in removing ALL uninstallation functionality.

You can pull that off by editing the behavior in the MSI code and changing the uninstall requirement or in a worse case scenario create a new product code. Tech support may yell at me on that one, warning against some potential issues doing it that way, but it can be made to work either of the above ways.

I had to do the latter with one project, because of not following instructions, the patching system would not work because the project used a letter in the version instead of a number. Unfortunately the program has been around for 15 years and always used a letter in the version field and all full installs allowed it. I did notice that you are warned in the latest version of IA with a tooltip, but can't say if it has always been there or not.