MSB8006: The Platform for project '{0}' is invalid. Platform='{1}'. This error may also appear if some other project is trying ...

MSB8006: The Platform for project '{0}' is invalid.  Platform='{1}'. This error may also appear if some other project is trying to follow a project-to-project reference to this project, this project has been unloaded or is not included in the solution, and the referencing project does not build using the same or an equivalent Platform.