Debugger doesn't work, "Frame not in module"?

I had a similar problem while developing a library for use in Unity. The debugger couldn't step into code in my library, even though I added the library project to my VS solution. The problem turned out to be that I had to copy the .dll file into the Unity project directory subtree for Unity to be able to use, and this created a reference from VS to the copy, but the copy location did not include the .pdb file from the VS project directory. Copying the .pdb file to the same Unity directory as the .dll file solved the problem. (Remember to copy the .pdb every time you create and copy a new .dll; you can make VS do this for you in the project properities build settings.)

This happens in vs2013,and 2015. You have to change your exception settings and make sure that you tick the parent option “Common Language Runtime Exceptions”.By default Visual Studio seem to have that option ticked off which is why you get the Frame Not In Module error.