Uninstall the old version, and then re-install the new one.
Otherwise, you'll need to create an installer that is capable of updating your application. The reason is that the ProductCode
GUID, which identifies the application about to be installed to Windows, is already in use by the previous instance of your application.
You can specify that your installer remove any previous versions of the application that it finds by setting the RemovePreviousVersions
property to True. You'll also need to increment the ProductCode
and PackageCode
to reflect that this is an upgraded version of the application. You do not want to change the ProductCode
if you go this route, because then Windows will see what's about to be installed as an entirely different application. You don't mention what you're using to create the installer, so it's difficult to provide any more details. In Visual Studio, you can set these properties in the designer:

Or, if you're using WiX, you should see the answers to this question.