UE 5.8 – UnrealBuildTool BuildRules DLLs blocked by Windows Smart App Control (0x800711C7)

Development Programming & Scripting
,
1

Dear Unreal Engine Community and Epic Games Team,

I am developing a Meta Quest 3 VR application using Unreal Engine 5.8 on Windows.

Problem

Windows Smart App Control blocks the unsigned BuildRules DLL assemblies automatically generated by UnrealBuildTool (UBT), preventing the project from compiling.

Environment

  • Unreal Engine 5.8

  • Windows with Smart App Control enabled

  • Target: BonieAvatarEditor / Win64 / Development

  • Deployment platform: Meta Quest 3 / Android

  • Native C++ plugin development for hand and finger tracking

Reproduction and findings

We tested two build approaches:

  1. Auxiliary EditorHost build:
    QuestBuild/MotionTest03/EditorHost/Intermediate/Build/BuildRules/EditorHostModuleRules.dll

  2. Standard project build:
    Intermediate/Build/BuildRules/BonieAvatarModuleRules.dll

Both builds were blocked while loading their generated rules assemblies, before C++ compilation.

Error code: 0x800711C7

Windows security events: 3033, 3077, 3089

Policy: VerifiedAndReputableDesktop

The generated rules DLLs are unsigned. We have not disabled Smart App Control or modified Windows security policies.

Questions

  1. Is this a known compatibility issue with Unreal Engine 5.8 and Windows Smart App Control?

  2. Is there an officially supported way to compile C++ projects while keeping Smart App Control enabled?

  3. Is there a supported signing mechanism for dynamically generated UBT BuildRules assemblies?

  4. Is there a fix, patch, or recommended build configuration that avoids this issue?

Relevant UBT logs and Windows event records can be provided upon request.

Thank you for your assistance.