Uninstall a application during installation not working

Question

I am developing WPF application in C#. Currently my msi install the current application in machine.I need to uninstall two supporting application of existing version during

Answer 1

There is a mutex in MSI that prevents concurrent installation / uninstalls. Everything has to happen within the context of a single installer. That said, the way to do that is to author rows into the Upgrade table to teach FindRelatedProducts and RemoveExistingProducts to remove the additional installed MSIs.

You don't mention what you are using to create your MSI so I can't show you how to do that.

You've now mentioned that you are using VDPROJ. This tool doesn't support authoring what you are trying to do. My suggestion is to refactor using Windows Installer XML (WiX) and author multiple Upgrade elements to remove the various products.