Visual Studio Rebuilds unmodified projects

Question

So, as the title reads, I have a VS2010 solution with ~50 projects in it right now. If I make a change to a \"top level\" project that nothing references then VS still rebui

Answer 1

I had this same problem and it turned out to be related to a couple of project that had a copy local reference to a dll in their own output directory.

The key to finding this was having diagnostic output set for the build output, but also knowing what to look for in the log. Searching for: 'not up to date' was the key.