Sometime last night MD started acting up I believe with the debugger - I have a self hosted nancy app that has been working fine for ages. I started getting errors , first was unable to resolve localhost switching to 127.0.0.1 solved that. Then I was running into linq errors that made no sense and calls failing with method not found errors that go to declaration had no problem finding ... BUT if I run the app without debugging, everything works fine. I tried a rebuild hoping that would straighten things out but no luck. My next step is to restore a snapshot I created yesterday that was hopefully before the issue started. I don't believe anything has been installed or updated - any idea what could be going on ? some corrupted cache somewhere maybe ?