This article documents a tricky Unreal Engine 5.3 plugin packaging failure caused by an ArgumentNullException inside UnrealBuildTool’s ModuleRules.IsValidForTarget. It walks through diagnosing the issue, explains how stale ModuleRules assemblies and UBT’s reflection over module attributes can trigger the crash, and shows how to fix it by hardening IsValidForTarget, deleting cached *Rules.dll files, and manually rebuilding UBT via dotnet. The result is a reliable packaging pipeline for complex C++ plugins, with practical steps you can apply to similar build-time crashes in your own projects.
https://dev.epicgames.com/community/learning/tutorials/5E8b/unreal-engine-fixing-a-ue-5-3-plugin-packaging-crash-caused-by-unrealbuildtool