SSAS : The ID does not have a 'Database' parent Error

Today, I had a 'great' idea adding a cube in SQL Server Analysis Services (SSAS) to an existing project for testing purposes. I ran into some strange errors : "The does not have a 'Database' parent" Error. Also, a red cross in the cube icon in the solution explorer was visible. In this blogpost I'll show the errors, the possible cause and how to fix this..