Source file '' could not be found

Question

I have some solution already created I need to work with, but I get these:

Warning 1   At least one file is missing the 'RelPath' attribute.   SolutionName

Error   2   Source file '' could not be found   C:\Users\me\Desktop\someDir\someDir\CSC SolutionName

I use VS Express 2013 for Desktop. I get this error when I click rebuild solution

Why I get this error and how to fix it?

Solution

Create a backup of your project file.

In solution explorer, right click your project and unload it. Then right click again and "Edit project file".

There you can inspect your files. There should be a problem with one of them, like lacking a file name, or something different from the other files. Remove the attributes regarding that file, save the project, right click, reload project.