Trying to create a setup project in Visual Studio 2015. When I add my main project, no dependencies are added; not my other projects (dll's), no Nuget packages, not even the .Net Framework.

I did try adding those project dll's manually, but whether I do or don't, I get this build error every time:

```
------ Starting pre-build validation for project 'ProjectInstaller' ------ 
ERROR: An error occurred while validating.  HRESULT = '80070057'
------ Pre-build validation for project 'ProjectInstaller' completed ------

```

Of note, this error only appears in the output, not the error list. So any ideas why the dependencies are not added? Why the build is failing? What does that error code even mean?

(As an afterthought, I have successfully built an install file on a different solution set altogether; I'm thinking maybe it's some setting in my project properties).