How to fix the black screen with hourglass bug on Oculus Rift

[Windows Central]

How do I fix the black screen hourglass bug on Oculus Rift?
Using your Oculus Rift with Steam VR is usually a painless experience, but some people are reporting a bug that essentially ruins a gaming session. In the middle of playing, you will be switched over to a black screen with an hourglass in the middle — the default loading screen for the Rift. The problem: the black loading screen doesn't go away until you restart the game.

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