This project cannot be viewed in the object browser because it is unavailable or not yet built

Question

I have a VS2013 solution that has many projects all C# with framework 4.5 When I try and rebuild all projects in the solution I get an error message

This project cannot be viewed in the object browser because it is unavailable or not yet built

I note that in the start up project the references to the other DLLS appear as though the DLLs are missing.

I can actually get the solution to run by building each project one at a time, and then double clicking the reference in the start up project.

Eventually I have gotten rid of all the bad reference icons in the start up project and the solution will run.

However as soon as I rebuild the whole solution the bad references re-appear.

Strangely Build works, but Re-Build doesn't, and Clean and Re-build doesn't.

I do have the following set up.

Project Templates References Project DomainLayer
Project DataLayer References Project Templates and Project DomainLayer

Thus VS needs to build DomainLayer first then Templates then DataLayer.... perhaps it can't work this out?

What is going on?

Answer 1

Although you could build projects individually, but cannot rebuild solution. It sounds to be problem with target framework. Go to project properties and ensure you're targeting Framework 4.5 for all projects. Somewhere in some project this might be missing.