I ran into this problem when upgrading from WiX v3 to v4 and want to provide an answer that worked for me, as i did not find any here.
The Problem:
In my case i was trying to automate the proccess for upgrading my installer when changes are made to the source code. So i made a setup.build with a couple of targets. They included
- Publishing my Web App
- harvesting it
- building the installer
The problem arises after the harvesting part, because when building the installer which is in WiX v4, it complains about the namespace added in the harvested file which is v3.
What to do?