Setup project not finding the dependencies of a project primary output

Question

In Visual Studio 2008 I've added a project's primary output to a setup project but the project's dependencies are not being found.

If I look at the properties of the primary output the Dependencies property shows as (None). If I look a little deeper then I can find that the Dependencies property under the KeyOutput property has the projects dependencies listed and some of those have yellow warning triangles next to them.

This has only started happening since I put the startup project into source safe.

Because of this problem the setup project will not build and I get this error:

------ Starting pre-build validation for project 'PROJECT' ------ 
ERROR: An error occurred while validating.  HRESULT = '80004005'

Answer 1

I ran into this problem when branching and combining various versions of my libraries into projects without making sure that the libraries all referenced the correct versions of each other. Deleting and re-adding my inter-library references fixed the problem.