UE5.2 Editor Crashes When Open A Project From 5.1

[mjiggidy]

I have an OpenXR/Lumen/Nanite project that runs fine in Unreal 5.1. If I try to open it in 5.2, the editor crashes as soon as the project is loaded. The crash reporter has the following error message:

Assertion failed: CurrentGPUVirtualAddress != 0 [File:D:\build\++UE5\Sync\Engine\Source\Runtime\D3D12RHI\Private\D3D12DescriptorCache.cpp] [Line: 587]

If I edit the project’s DefaultEngine.ini to change the RHI to from DirectX 12 to DirectX 11, the project opens fine. But this is not an option because I need DirectX 12, which by the way works perfectly fine in 5.1.

I am on Windows 10, RTX 3080, latest Nvidia GameReady drivers.

[Elleclouds]

How did you fix this?

[C.Marschott]

Try disabling vr.InstancedStereo if you have that enabled, seeing as you have a VR project you might have the same issue as me.
It’s only a workaround, though.

[mjiggidy]

Oh, well now that’s interesting! Disabling Instanced Stereo did the trick. How did you figure that out? Is this a known thing?

Thanks for this tip! Like you say, it’s a workaround and I’d like to get muh Instanced Stereo back, but at least I can continue work on my project in 5.2.

[C.Marschott]

I tried commenting out all rendering settings in the DefaultEngine.ini to see if that prevents the crash and when it did, I proceeded with divide and conquer to figure out which setting(s).

It is a known thing, apparently it was a fluke that it worked in 5.1 and official ISR support for Nanite comes in 5.3.

[LiveSimulator]

Wait. How can it just “WORK” in 5.1 but then 5.2 it doesn’t? Is it just a deep-engine backend thing with how the rendering is setup?