Debug cocktail ans Caliburn micro source code

The easiest way is probably to download the source code and build the debug assemblies on the machine you like to debug on, then reference the assemblies you just built. Make sure that the *.pdb files are found in the same folder as the assemblies. You will then be able to step through the code. Visual Studio will find the source in the same place you built the assemblies from. For Caliburn Micro, make sure you download the 1.3.1 source code as that is the version that Cocktail currently uses.