If you got this error "Error: The version of the .NET Framework launch condition '.NET Framework 4' does not match the selected .NET Framework bootstrapper package" then you are at the right place.
Few days back i installed "Visual Studio 2010", i am always very excited testing new software.
So i created a new project and under target .Net Framework i selected "3.5 Framework".
I added a New Project Setup& Deployment Installer package. I then compiled it, and tried installing. The application came up with ".Net 4.0 Client framework required". But wait i was targeting .Net 3.5 framework so why did i get asked for ".Net 4.0 Client Framework"?
Well after doing some searches and going through forums, i finally discovered that in the installer project for some strange reason Visual Studio still keeps the launch condition prerequisite as ".Net 4.0".
Here are the steps to resolve this issue.
1) select installer project
2) click on the icon on top "Launch Conditions Editor" its the icon with a binoculars.
3) Under Launch Conditions, Select ".Net framework" on the right in "Properties" Select "Version" you will see a drop down. change the framework to your target framework.
Build and install.