This is probably caused by a problem in the constructor of one of your C++ classes.
Try launching the editor from Visual Studio in Debug Editor mode. Open Visual Studio, set your project to be the startup project by right-clicking on it in the solution explorer and picking “set as startup project”, set the configuration to “DebugGame Editor,” and then hit the green play arrow next to configurations to run.
Your editor will still crash, but it should give you a useful callstack and take you right to where it happened.