How to fix a SteamVR compositor error in Windows Mixed Reality

Windows Mixed Reality (WMR) has been opened up for integration with SteamVR, bringing a ton of new content and possibilities. Since these two systems weren't originally designed for each other, there are some bugs you might come across. One error you might encounter is "Shared IPC Compositor Connect Failed (400)," which has to do with where your monitor and WMR headset aren't plugged into the same video adapter in your PC.

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Where do I plug in the Windows Mixed Reality headset?

In order for WMR to work properly, you want to ensure that your monitor and WMR headset are plugged into the same video adapter in your PC. If you're using a desktop, you might have two dedicated graphics cards (GPU), or you might have an adapter for integrated graphics and one for a dedicated card.

That lone HDMI port below the audio inputs might look tempting, but it isn't connected to the dedicated GPU in our PC.

In our case, this PC has a selection of ports that go directly to the NVIDIA GTX 980 GPU, while there's also an HDMI port sitting alone that's meant for use with the integrated Intel HD Graphics 530 in the Intel Core i7-6700 processor (CPU).

Before making any other changes, be sure to plug your regular monitor and WMR headset into the same video adapter — that means both into ports coming from the same GPU.

How to set your standard monitor as a primary display

Now that everything is plugged in where it should be, you should be able to put on the headset and enjoy. However, your PC might recognize the WMR headset as a standard monitor, which will no doubt interfere with the experience. Here's how to set your regular monitor as a primary display to potentially fix this problem.

  1. Click the Start button.
  2. Click the Settings button.
  3. Click System.

    Click the Settings button. Click System.

  4. Click Display.
  5. Click Identify. You will see a number pop up in the corner of your screen. It should say either 1 or 2 depending on how many monitors you have connected.

    Click Display. Click Identify.

  6. Click the display with the number that corresponds to your regular PC monitor.
  7. Click the dropdown menu below Multiple displays.

    Click the display. Click the dropdown menu.

  8. Click Show only on X. This number should correspond with the number that shows on your standard monitor.
  9. Click Keep changes.

    Click Show only on X. Click Keep changes.

Restarting your PC after these changes wouldn't hurt, and following that, attempt to launch WMR and SteamVR as usual.

More resources

Looking for more to do with Windows Mixed Reality? Be sure to check out our Ultimate Guide for a ton of information, and for more troubleshooting help, we've amassed some of the most common issues into one guide.

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