Troubleshooting Guide

Compilation Errors

"Cannot find UnrealBuildTool.exe"

Cause: Visual Studio C++ workload not properly installed or UE can't find it.

Solutions:

1. Open Visual Studio Installer → Modify → Ensure "Game development with C++" workload is installed
2. Restart Epic Games Launcher after VS installation
3. Verify UE Editor → Edit → Editor Preferences → Source Code → Source Code Editor is set to Visual Studio 2022

"Module 'Platformer' could not be loaded"

Cause: C++ compilation failed or module not properly built.

Solutions:

1. Close UE Editor completely
2. Delete Binaries/ and Intermediate/ folders from your project
3. Right-click .uproject file → "Generate Visual Studio Project Files"
4. Open .sln in Visual Studio → Build → Build Solution
5. If successful, launch UE project from Visual Studio (F5) or double-click .uproject

"Unresolved external symbol" Errors

Cause: Missing module dependencies or incorrect linking.

Solutions:

1. Check Source/Platformer/Platformer.Build.cs includes required modules:

   PublicDependencyModuleNames.AddRange(new string[] {
       "Core", "CoreUObject", "Engine", "InputCore", "EnhancedInput",
       "AIModule", "UMG", "GameplayTasks", "NavigationSystem"
   });

2. Ensure UCLASS/USTRUCT macros are properly declared
3. Verify forward declarations vs. full includes in headers

Enhanced Input Issues

"Input Action not found" or Input Not Responding

Solutions:

1. Verify Input Action assets exist in Content Browser
2. Check Input Mapping Context is created and configured
3. Ensure IMC is added to player controller:

   // In BeginPlay or similar
   if (UEnhancedInputLocalPlayerSubsystem* Subsystem =
       ULocalPlayer::GetSubsystem<UEnhancedInputLocalPlayerSubsystem>(GetLocalPlayer()))
   {
       Subsystem->AddMappingContext(InputMappingContext, 0);
   }

4. Verify action bindings in SetupPlayerInputComponent

"Enhanced Input plugin not found"

Solutions:

1. UE Editor → Edit → Plugins → Search "Enhanced Input" → Enable
2. Restart editor when prompted
3. If still missing, verify UE5.1+ (Enhanced Input built-in from 5.1)

Git LFS Problems

"Git LFS not tracking files" or Large Files in Regular Git

Solutions:

1. Verify Git LFS installed: git lfs version
2. Initialize in repo: git lfs install
3. Check .gitattributes file exists with proper patterns:

   *.uasset filter=lfs diff=lfs merge=lfs -text
   *.umap filter=lfs diff=lfs merge=lfs -text

4. Migrate existing files: git lfs migrate import --include="*.uasset,*.umap"

"Git LFS bandwidth limit exceeded"

Solutions:

• Use GitHub Pro for increased LFS bandwidth
• Or consider alternative: GitLab (free LFS) or Azure DevOps
• Minimize asset size during development (use placeholders)

Runtime Issues

"Character doesn't move" in PIE

Debugging checklist:

1. Check Enhanced Input setup (common cause)
2. Verify SetupPlayerInputComponent calls parent: Super::SetupPlayerInputComponent(PlayerInputComponent);
3. Ensure player controller possesses the character
4. Check movement component settings (not disabled)
5. Add debug logs in Move function:

   UE_LOG(LogTemp, Warning, TEXT("Move called with value: %s"), *Value.ToString());

"Camera not following character"

Solutions:

1. Verify SpringArm and Camera components attached correctly
2. Check SpringArm collision (might be hitting world geometry)
3. Ensure camera lag settings are reasonable (not 0, not too high)
4. Verify bUsePawnControlRotation = false on SpringArm for platformer camera

"AI not working" - Enemy doesn't move or react

Debugging steps:

1. Check AI Controller assigned to enemy pawn
2. Verify Behavior Tree asset exists and is valid
3. Ensure NavMesh exists in level (Build → Build Navigation)
4. Check Blackboard keys are correctly named and typed
5. Add debug logging in BT tasks
6. Use AI Debugging tools: Gameplay Debugger (apostrophe key)

Plugin Issues

"Plugin 'XXX' failed to load"

Solutions:

1. UE Editor → Edit → Plugins → Search plugin name → Enable
2. Restart editor when prompted
3. For code plugins, ensure proper module dependencies in .Build.cs
4. Check plugin compatibility with UE version

Missing UMG/Widget functionality

Solutions:

1. Enable UMG plugin: Edit → Plugins → "UMG" → Enable
2. Add "UMG" to PublicDependencyModuleNames in Build.cs
3. Include headers: #include "Components/WidgetComponent.h"

Performance Issues

"Slow compilation times"

Solutions:

1. Use SSD for UE installation and projects
2. Exclude project folders from antivirus real-time scanning
3. Close unnecessary applications during compilation
4. Use Unity builds in Build.cs (for larger projects):

   bUseUnityBuild = true;

"Editor running slowly"

Solutions:

1. Lower editor quality: Settings → Engine Scalability Settings → Low
2. Disable real-time rendering in viewport
3. Close unnecessary editor tabs/windows
4. Consider using smaller test levels during development

Project Structure Issues

"Can't find header files" or IntelliSense errors

Solutions:

1. Regenerate project files: Right-click .uproject → Generate VS Project Files
2. Refresh VS Code: Ctrl+Shift+P → "C/C++: Refresh IntelliSense"
3. Verify proper include paths in VS Code settings
4. Use forward declarations in headers, full includes in .cpp files

Getting Help

When stuck:

1. Check UE5 Documentation: docs.unrealengine.com
2. Unreal Engine Discord/Forums community
3. Search specific error messages on AnswerHub/Reddit
4. Use UE's built-in debugging tools (Output Log, Blueprint Debugger, etc.)

Before asking for help:

1. Include your UE version, VS version, and OS
2. Provide the exact error message
3. Share relevant code snippets
4. Mention what you've already tried

Debugging mindset:

• Make small, incremental changes
• Test frequently
• Use logging extensively during development
• Isolate problems (disable other systems to test one thing)
• Keep a working backup before major changes