Resolving IPC Error 400 with Steam VR Compositor

As a long-time user of Steam VR, I've had my fair share of issues, but nothing has been more frustrating than encountering an IPC error 400 with no clear solution. Like many others, I was told by support to try various troubleshooting steps, but none of them seemed to work. That was until I stumbled upon a potential fix that might just help some of you out there who are experiencing the same issue.

For those who may not know what an IPC error is, it's short for Inter-Process Communication error. In this case, the error 400 specifically refers to a problem with the Steam VR compositor. So, what can you do to resolve this issue?

According to Steam support, one of the key factors that could be contributing to the problem is your graphics setup. If you have an SLI/CrossFire or multi-GPU configuration, make sure that your display devices are connected to the same GPU. Similarly, if you're using a laptop, ensure that you're not defaulting to integrated graphics and instead, prefer maximum performance.

To do this, follow these steps:

1. Go to Nvidia Control Panel > 3D Settings > Manage 3D Settings > Preferred graphics processor: High Performance NVIDIA processor (select this).

2. If you're using a laptop, set your machine to 'prefer maximum performance'.

3. Connect both your primary display(s) and your VR device to your dedicated GPU.

Another potential solution is to try running SteamVR in beta mode. I know that might sound counterintuitive, but according to some users, it can help resolve the issue. However, be aware that using the beta version may also introduce new bugs or problems.

I've tried a few other troubleshooting steps as well, including switching from HDMI to DisplayPort and uninstalling and reinstalling SteamVR. While these didn't solve the problem for me, they might work for someone else. Additionally, I noticed that when I build and run a VR scene, everything works fine, but trying to enable None instead gives me a warning and nothing goes through the headset.

If you're experiencing similar issues with your Steam VR setup, I hope these steps help you resolve the problem. Remember to try out different solutions until you find one that works for you. Happy gaming!

Steam vr compositor 400