InstallAware

I am now using IA 8 but I have found a similar issue to what you desscribed in this post and I was wondering if you ever received a solution to it.

My issue is that if I install a default and a non default instance of version 1 of my product, then install a version 2 (thereby upgrading the default instance of version 1) I receive the "network resource not found" error, but it is pointing to look at the LastUsedSource registry key(as Gareth pointed out) for the non default instance of version 1!

I have debugged through my IA code, but it fails on the 'Apply Install' step, I have also changed product numbers and all other guids in the IA project but the issue still happens, when I have 2 instances of version 1 installed.

Anyone know a reason why it is looking at the incorrect registry entry?

Upgrades with multiple instances existing can be very complex and are not officially supported. Old versions should each be uninstalled - you can do this even from your own code in the new version with MSIcode scripting.