PIE: VR Preview Crash with Assertion failed: PipelineState.FrameState.predictedDisplayTime

Development Platform & Builds XR Development
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Hello there,

we encountered a crash we currently don’t know how to fix. Every time the application is started in PIE: VR Preview and a Windows Mixed Reality Headset is connected the editor crashed because following assertion failed:

Assertion failed: PipelineState.FrameState.predictedDisplayTime

It seems to be a problem with OpenXR. OpenXR is the only VR Plugin enabled.

The crash extends to packaged builds as well. It appeared first during tests on systems we didn’t develop on.

Did anyone encounter the same or a similar problem and knows a solution? Could someone outline what that failed assertion might mean?

Here is the full Error Report:

Assertion failed: PipelineState.FrameState.predictedDisplayTime [File:D:\build\++UE5\Sync\Engine\Plugins\Runtime\OpenXR\Source\OpenXRHMD\Private\OpenXRHMD.cpp] [Line: 1950]



UnrealEditor_OpenXRHMD
UnrealEditor_OpenXRHMD
UnrealEditor_HeadMountedDisplay
UnrealEditor_Engine
UnrealEditor_RenderCore
UnrealEditor_RenderCore
UnrealEditor_Renderer
UnrealEditor_Renderer
UnrealEditor_Renderer
UnrealEditor_Renderer
UnrealEditor_Renderer
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_RenderCore
UnrealEditor_RenderCore
UnrealEditor_Core
UnrealEditor_Core
kernel32
ntdll

Thanks in advance. I appreciate every help incoming.

1 Like
2

The assertion means the time value for the frame is invalid. Either there is a bug in the engine that prevents the frame state from updating properly, or it’s an issue with the OpenXR runtime. It might be worth checking that other OpenXR applications work on the affected system.

3

The problem occurred with Windows Mixed Reality (WMR). On the other devices WMR had to be installed and setup. We don’t use controllers. Therfore we thought that it is enough to start the Mixed Reality-Portal without further setup. How wrong we have been…
It is necessary to define the input device first. If you don’t use controllers you have to select Mouse and Keyboard with Win + Y and looking at the diamond in the center.
After that setup everything works fine. No exceptions, asserts or crashes.

@Rectus_SA Your advice encouraged us to dive deeper into the OpenXR topic and WMR. Thanks for that!