I sometimes get this problem when I try to manually edit projects/solutions generated by our CMake system. I solve it manually:
- Open the dependent .vcproj file in your favorite text editor.
- Find <ProjectReference> tag corresponding to the dependency you want to remove (the include attribute of the tag will contain the name of the dependency project).
- Remove the whole <ProjectReference> element (i.e. starting with <ProjectReference> and ending with </ProjectReference> inclusive). Save the file.
- Reload the solution.