I downloaded FiddlerCore by today because Microsoft Message Analyzer requires it if one wants to inspect HTTPS traffic. It seems that version 4.6.20172.35715 of the FiddlerCore library is no longer compatible with Microsoft Message Analyzer. What I can guess from the error message given by the MMA is, that an overload of a certain method has been removed (or changed); to be specific MMA expects a method named Startup(int, bool, bool) in Fiddler.FiddlerApplication...