When rendering in 5.7+ (I say + because I’ve seen this from 5.7.0 through the recent 5.7.2) using Movie Render Queue, every sample of the render is painfully slow, and you get a blink of the “Compiling Shaders” window. In the logs, these files report failing to compile, thus slowing the renders.
[2026.01.26-14.56.46:647][887]LogShaderCompilers: Warning: Failed to compile Material /Engine/BufferVisualization/AmbientOcclusion.AmbientOcclusion for platform PCD3D_SM6, Default Material will be used in game.
Shader debug info dumped to: "D:\Curve_Projects\FOLIO_VFX\SlowMotionDrift\Saved\ShaderDebugInfo\PCD3D_SM6\AmbientOcclusion_3ae0198ee8f1fd60\Default\FLocalVertexFactory\TBasePassPSFNoLightMapPolicySkylight\3_0bb22bb2aadf7315"
C:\Program Files\Epic Games\UE_5.7\Engine\Shaders\Private\BasePassPixelShader.usf(2460,42): Shader TBasePassPSFNoLightMapPolicySkylight, Permutation 3, VF FLocalVertexFactory:
/Engine/Private/BasePassPixelShader.usf:2460:42: error: use of undeclared identifier 'AdjustedDualBlendAdd'
AddOITSample(uint2(In.SvPosition.xy), AdjustedDualBlendAdd, AdjustedDualBlendMul, MaterialParameters.ScreenPosition.w);
^
C:\Program Files\Epic Games\UE_5.7\Engine\Shaders\Private\BasePassPixelShader.usf(2460,64): Shader TBasePassPSFNoLightMapPolicySkylight, Permutation 3, VF FLocalVertexFactory:
/Engine/Private/BasePassPixelShader.usf:2460:64: error: use of undeclared identifier 'AdjustedDualBlendMul'
AddOITSample(uint2(In.SvPosition.xy), AdjustedDualBlendAdd, AdjustedDualBlendMul, MaterialParameters.ScreenPosition.w);
The “solution” was to disable the “Enable Order Independent Transparency” feature, which doesn’t feel like a valid solution, but it means I’m not crashing and waiting hours for renders anymore.