I am having the same issue with Oculus Rift DK2. If it is powered on when attempting to launch the 4.7.3 editor it crashes and wants the user to give a report (nice). If you turn it off you can get the editor to launch, and your project, but I could never get the display to actually work (power indicator displays orange saying no video signal).
For now I have to use the “Extend Desktop to the HMD” display mode in the “Rift Display Mode” options, most have to orient their display to be horizontal, and then everything works correctly but just not ideal. Hopefully this issue can be resolved soon so that we can use the Direct HMD display mode.