Expect deep dive into a few interesting investigations we faced on .NET team in the last decade. War stories about: • Investigations spanning years, • Dormant bugs coming to life after a decade, • Root-causes leading to surprising places, • How we rooted-cause problems with minimal information available, • Shocking impact of bugs on real world. We will also cover: • Root-causing HW bugs (avoid the one-machine problem), • The value and art of minimal repro, • Innovation and compatibility - the age-old rivals.