Build Error: Module ‘MyModule’ Is Not Found in the Module Hierarchy

What It Means & How to Fix It in UE5

🧠 Why You’re Seeing This Error

This error means Unreal Engine couldn’t find a module you referenced — usually in your .Build.cs, .Target.cs, or .uproject/.uplugin file — because it’s missing, not registered correctly, or not visible to the engine during build.

It often shows up when:

You reference a module in ExtraModuleNames or PublicDependencyModuleNames, but that module isn’t part of your project or plugin
You added a new module but forgot to regenerate project files
The module folder doesn’t follow Unreal’s expected layout
You renamed or moved a module but didn’t update its build files

💥 Example Error Message

UnrealBuildTool: ERROR: Module 'MyModule' is not found in the module hierarchy

🛠️ What Usually Causes This

❌ You Listed a Module That Doesn’t Exist

ExtraModuleNames.Add("MyModule"); // ❌ But the actual module folder doesn't exist

❌ The Module Exists, But Isn’t in the Project’s Source Tree

Unreal only sees modules that follow the proper structure, like:

plaintextCopyEditProjectRoot/
└── Source/
    └── MyModule/
        ├── MyModule.Build.cs
        └── (source files)

❌ You Renamed a Module But Didn’t Update Its References

If you renamed the module folder or .Build.cs class but didn’t change all references, the build fails.

❌ You Added a Module But Didn’t Regenerate Project Files

Even if the folder is correct, Unreal won’t pick up the new module until you regenerate.

✅ How to Fix It – Step-by-Step

✔️ 1. Make Sure the Module Folder and `.Build.cs` File Exist

The expected layout is:

plaintextCopyEditProjectRoot/
└── Source/
    └── MyModule/
        ├── MyModule.Build.cs
        ├── Private/
        └── Public/

The MyModule.Build.cs file must match the folder and module name.

✔️ 2. Check Your `.Target.cs` or `.uplugin` References

ExtraModuleNames.Add("MyModule"); // ✅ Must match the folder + Build.cs class exactly

Check for typos, incorrect casing, or outdated names.

✔️ 3. Regenerate Visual Studio Project Files

After verifying your module exists:

Right-click your .uproject → Generate Visual Studio project files
Reopen your solution and rebuild

This step is crucial — Unreal won’t recognize new modules without it.

✔️ 4. If It’s a Plugin Module, Check Your `.uplugin` File

Make sure it’s registered in your plugin descriptor:

jsonCopyEdit"Modules": [
  {
    "Name": "MyModule",
    "Type": "Runtime",
    "LoadingPhase": "Default"
  }
]

And the actual module folder exists at:

Plugins/MyPlugin/Source/MyModule/

✅ Summary: How to Fix “Module ‘MyModule’ is not found in the module hierarchy” in UE5

Cause	Fix
Missing or misnamed module folder	Ensure `Source/MyModule/` exists and contains `.Build.cs`
Typo or mismatch in `.Target.cs` or `.uplugin`	Match module name exactly, including case
Didn’t regenerate project files	Right-click `.uproject` → Generate project files
Invalid plugin/module structure	Follow UE5’s folder layout for plugin or project modules

UE5 Compilation Errors