UE5.3 PackagingResults: Error: Unknown Cook Failure

[SgtFlexxx]

Hi all,

I migrated my project a few times before between versions (4.27 → 5.2 → 5.3) (I also moved it from my D drive to my C drive at one point during 5.3), and I no longer seem to be able to package the project due to a cook error. Is anyone able to decipher the error?

LogInit: Display: Warning/Error Summary (Unique only)
LogInit: Display: -----------------------------------
LogInit: Display: LogShaders: Error: Virtual shader source file name "C:\Engine\Private\BasePassPixelShader.usf.intermediate.hlsl" should be absolute from the virtual root directory "/".
LogInit: Display: LogShaders: Error: Backslashes are not permitted in virtual shader source file name "C:\Engine\Private\BasePassPixelShader.usf.intermediate.hlsl"
LogInit: Display: LogShaders: Error: Extension on virtual shader source file name "C:\Engine\Private\BasePassPixelShader.usf.intermediate.hlsl" is wrong. Only .usf or .ush allowed.

[Jimbohalo10]

@SgtFlexxx

LogShaderCompilers: Warning: Failed to compile Material /Interchange/gltf/M_SpecularGlossiness.M_SpecularGlossiness (MI:/Interchange/gltf/MaterialInstances/MI_SpecularGlossiness_Blend.MI_SpecularGlossiness_Blend) for platform PCD3D_SM5, Default Material will be used in game.
  err0r X8000: Validation Error: source component 0 in temp r2 not initialized. Opcode #54 (count is 1-based)

LogMaterial: Warning: Cooking a material resource (in M_SpecularGlossiness hierarchy) that doesn't have a valid ShaderMap! Shadermap pointer is null.
LogCook: Display: Cooked packages 4356 Packages Remain 2 Total 4358
LogCook: Display: Cooked packages 4357 Packages Remain 1 Total 4358

hi @SgtFlexxx
Shader failure
(MI:/Interchange/gltf/MaterialInstances/MI_SpecularGlossiness_Blend.MI_SpecularGlossiness_Blend)
its a broken material
MI_SpecularGlossiness_Blend is corrupt and cannot be built

[SgtFlexxx]

I think those warnings are worth noting, but I don’t think what’s stopping my project from cooking, as it just sounds like it’ll use the default material in that material’s place. I think the actual errors that are stopping the cook are further down in the log (but I don’t know what they mean or how to fix them)

LogInit: Display: Warning/Error Summary (Unique only)
LogInit: Display: -----------------------------------
LogInit: Display: LogShaders: Error: Virtual shader source file name "C:\Engine\Private\BasePassPixelShader.usf.intermediate.hlsl" should be absolute from the virtual root directory "/".
LogInit: Display: LogShaders: Error: Backslashes are not permitted in virtual shader source file name "C:\Engine\Private\BasePassPixelShader.usf.intermediate.hlsl"
LogInit: Display: LogShaders: Error: Extension on virtual shader source file name "C:\Engine\Private\BasePassPixelShader.usf.intermediate.hlsl" is wrong. Only .usf or .ush allowed.

Why all the interchange materials are broken is beyond me, but perhaps its linked to those 3 errors.

[Jimbohalo10]

@SgtFlexxx

C:\Engine\Private\BasePassPixelShader.usf.intermediate.hlsl" is wrong. Only .usf or .ush allowed.

The conversion from DirectX shader .hlsl to unreal virtual shader source file .usf
should be Possibly rename to

C:\Engine\Private\BasePassPixelShader.usf

[SgtFlexxx]

The file name is correct, but the file path is not. Im not sure why it’s setup this way and how to fix it. I already reinstalled 5.3

[MarGon]

I just transitioned from Unreal Engine 5.1 to 5.3 and encountered the exact same issue. After spending too many hours troubleshooting, I pinpointed the problem to having Shader Model 5 enabled while also using virtual textures. Apparently, virtual textures require Shader Model 6, and not disabling Shader Model 5 leads to these nerve-wracking and time-consuming packaging errors. To resolve this, you need to uncheck all SM5 in the project settings (Project Settings → Platforms → Windows). I hope this solves it for you too.

[SgtFlexxx]

Wow, I had spent a lot of time trying to figure out this error. I had ended up disabling substrate which similarly resolved my issue, but I think I prefer just disabling SM5 (as converting shaders back from substrate is a lot of pain).