Our progress [to 1 billion devices] is going to be dependent on a number of factors: the health of the PC ecosystem, enterprise deployments, and really the adoption of new device form factors," admits Myerson. "Increasingly our view of success if viewed through how the world is loving Windows 10 and it's measured by their engagement and customer delight." I pushed Myerson on whether Microsoft is giving up on the 1 billion figure, but he repeated the focus on success through how people are reacting to Windows 10. Once the free upgrade comes to an end in a month, it's reasonable to assume adoption of Windows 10 will slow unless there's an increased demand for 2in1 devices or PCs themselves.