
In the Portal, navigate to the "OpenXR" page and then, under Developer Features, select the Install button.

When using the HoloLens 2 emulator, the easiest way to install the OpenXR Tools for Windows Mixed Reality is through the Windows Device Portal. To find and install the OpenXR Tools app, on your HoloLens 2, go to the Store app and search for "OpenXR." It provides a demo of various OpenXR features and an OpenXR Runtime page that contains key information about the active runtime and current headset. If you're developing OpenXR applications for HoloLens 2 or PC VR, you might find this OpenXR Tools for Windows Mixed Reality app useful. Getting the OpenXR Tools for Windows Mixed Reality If that button is missing, the OpenXR runtime is already active.

To reactivate the Windows Mixed Reality OpenXR Runtime, on the Start menu, launch "Mixed Reality Portal" and then select "Fix it" at the top of the window.

If you've been using multiple VR headsets on your PC, keep in mind that the active OpenXR runtime may be changed by another vendor's system software. The Microsoft Store then keeps the runtime up to date. That's it! The Windows Mixed Reality OpenXR runtime is installed and made active automatically for all Windows Mixed Reality users.

To start developing OpenXR applications for immersive Windows Mixed Reality headsets: Getting started with OpenXR for Windows Mixed Reality headsets If you're using the emulator, the emulator image will reset each time you start it, and so your best bet is to just make sure that you have the latest version of the HoloLens 2 emulator image.
