In this paper we describe how we moved from ethnographic study to design and testing of a Mixed Reality (MR) system, supporting collaborative troubleshooting of office copiers and printers. A key CSCW topic is how remotely situated people can collaborate around physical objects which are not mutually shared, without introducing new interactional problems. Our approach, grounded in an ethnographic study of a troubleshooting call centre, was to create a MR system centred on a shared 3D problem representation, rather than to use video or Augmented Reality (AR)-based systems. The key drivers for this choice were that given the devices are sensor equipped and networked, such a representation can create reciprocal viewpoints onto the current state of this particular machine without requiring additional hardware. Testing showed that troubleshooters and customers could mutually orient around the problem representation and found it a useful troubleshooting resource. Author Keywords Ethnography...