Oculus Rift Sanity Check
If for some reason the Oculus HMD is not working first check that the Oculus plug-In is enabled. You can find the Oculus plugin under the Virtual Reality section in the Plug-in menu.
If the Rift is not working in a Packaged game, make sure that Start in VR is checked. Start In VR can be found by going to Project Settings > Description > Settings.