Unreal Engine 4 and 5 are both incredible game engines responsible for many of the best games we play today. While it is powerful and efficient, Unreal Engine can encounter issues that affect its functionality. Whether you’re dealing with Unreal Engine problems or specific Unreal Engine 5 issues, understanding how to troubleshoot can make all the difference.

Problems with blueprints, plugins, or the shader are common and can be pretty frustrating if you are a designer or developer. Thankfully, there are solutions to them which we are going to cover.

Whether you're new to Unreal Engine or an experienced developer, understanding how to troubleshoot issues is essential. If you're just starting, our Complete Guide to Unreal Engine is a great resource to help you master the basics before diving into troubleshooting.

Unreal Engine Crashes on Startup

Unreal Engine crashing on startup can result from outdated drivers, corrupted project files, or hardware compatibility issues. First, ensure your GPU drivers are up to date, as Unreal heavily relies on graphics processing. Next, delete the Saved, Intermediate, and Config folders from your project directory to remove potential corrupted files. If the issue persists, launch Unreal Engine in safe mode by holding Shift when opening the project. Disabling plugins or running the engine with DX11 (by adding -dx11 to the shortcut target) can also resolve crashes related to DirectX issues.

If Unreal Engine still crashes, check the Crash Reporter for error messages and logs that might indicate the cause. Updating Unreal Engine to the latest stable version or verifying its installation via Epic Games Launcher can also help. Sometimes, antivirus software may interfere with Unreal’s startup—try disabling it temporarily to test. If all else fails, reinstall Unreal Engine after completely removing its existing installation.

Lighting Build Stuck or Very Slow

Slow lighting builds are often due to a lack of RAM, CPU limitations, or Unreal Engine using CPU Lightmass instead of GPU rendering. First, check Task Manager (Windows) or Activity Monitor (Mac) to ensure that Unreal Engine has enough system resources. Reducing lightmap resolution and static lights can also speed up the build process significantly. Additionally, switch Static Lighting Level Scale to a higher value (e.g., 1.5 or 2) in the World Settings to reduce complexity.

If you are using GPU Lightmass, ensure your GPU drivers are updated and your Virtual Shadow Maps are enabled properly. Unreal may also struggle with lighting builds if swarm agent is not working correctly—check the Swarm Agent window for error messages and clear the cache if necessary. For large projects, consider using Distributed Lighting Builds to speed up processing across multiple computers.

Project Fails to Open or Load

A project failing to open usually indicates missing or corrupted files. First, ensure that all required assets are in the correct folders and have not been moved or deleted. Deleting the DerivedDataCache, Intermediate, and Saved folders often fixes loading issues by forcing Unreal Engine to rebuild necessary data. Additionally, opening a backup or an older version of the project (if available) can help determine whether a specific recent change caused the issue.

If Unreal fails to load due to plugin issues, launch the engine without the project and disable problematic plugins from the Plugins Manager before trying again. Another troubleshooting step is to migrate assets to a new project, which helps bypass corrupted configurations. If the engine prompts a missing module error, try rebuilding the project in Visual Studioor running Generate Visual Studio Project Files.

FPS Drops and Performance Issues

Performance issues in Unreal Engine usually stem from high-poly assets, unoptimized lighting, and excessive draw calls. Start by using Unreal's built-in profiler (stat unit, stat fps, or stat gpu in the console) to identify bottlenecks. Reducing dynamic lighting, switching materials to Unlit where possible, and enabling Level of Detail (LOD) for models can drastically improve FPS.

For CPU-bound issues, reduce AI calculations, enable Occlusion Culling, and lower shadow cascades. On GPU-heavy projects, optimize shaders by limiting real-time reflections and disabling unnecessary post-processing effects like Bloom and Ambient Occlusion. If you’re developing for lower-end devices, switch to Forward Rendering instead of Deferred Rendering for better performance.

If your system struggles with performance issues, using Unreal Engine on a cloud computer can provide the power you need without expensive hardware upgrades. Learn more about running Unreal Engine on a cloud PC to improve performance instantly.

Shader Errors in Unreal Engine

A functional shader is vital to designing a game that simulates reality, but shader errors are a common Unreal Engine problem that can affect your game's visual quality. The shader is the graphics component responsible for creating visual effects that simulate a realistic look of the game.

Shading errors often affect graphics quality and the overall performance of your game. A common shading error is a compilation error.

Compilation errors occur from a mistake in your shader file code which stops them from compiling as they should. There could be several causes:

• Syntax Errors

• Incorrect Configurations

• Missing Dependencies

Shader compilation errors can be frustrating, but learning the fundamentals of Unreal Engine shaders can help you troubleshoot effectively. Explore these tutorials for learning Unreal Engine to strengthen your skills and prevent common shader issues.

Solutions for Shader Errors

• Check the shader code for syntax errors: Syntax errors are the most common with shader issues. If you are unfamiliar with syntax or don’t know how to identify it, use an integrated development environment (IDE) or code editor to help you identify errors.

• Review your inputs: If your inputs are incorrectly defined or inaccessible, the shader won’t function correctly.

• Check file formats: Ensure that your files are saved in the correct format, referenced correctly, and saved in the suitable file destinations.

For those exploring other aspects of the engine, check out these top Unreal Engine courses and classes to deepen your skills.

Plugin Caused Errors

Plugins are assets that help you level up your project and enable developers to integrate third-party plugins that extend and improve Unreal Engine’s functionality. Unfortunately, plugins often have issues meshing with the Unreal Engine system, leading to Unreal Engine error messages.

Plugin errors can occur when certain dependencies are missing or when they’re incompatible with the Unreal Engine latest release.

Solutions for Plugin Errors in Unreal Engine

There are three possible solutions:

1. Check compatibility: Ensure the plugin is compatible with your version of Unreal Engine. You can usually see the supported versions of the plugin prior to installing it.

2. Update the plugin: Make sure the plugin isn’t old or out of date. If there are any available updates, it's best to do so and could also be the solution to your problem.

3. Reinstall the plugin: Remove the plugin and install it again. While it usually won’t solve the issue, it’s worth a try.

If all else fails, it’s best to look for a similar plugin with the same features. If you're unsure whether Unreal Engine is the right choice for your project, you might want to explore how it compares to Unity.

Packaged Build Errors

Another common issue game developers often face is packaging build errors. These errors result from missing or incorrect game files, often surfacing as Unreal Engine issues during the distribution phase, such as when Unreal Engine games are not working. This reflects poorly on us as game designers and developers, so it's essential to iron out any issues before distribution.

Solution for Packaged Build Errors

• Ensure correct configuration: Make sure the package settings are configured to your target platform and that every dependency is referenced correctly.

• Import necessary assets: Ensure that all necessary assets are correctly imported to avoid issues.

• Check for missing or corrupted files: Ensure there aren’t any missing or corrupted files, as these might be the root of your packaging build error. Different engine components can also conflict during deployment.

If you’re working in a team, consider learning how to create multiplayer Unreal Engine experiences to avoid these issues early on.

Blueprint Errors

Blueprints are vital to creating a functioning and immersive gaming experience. In Unreal Engine, the blueprint feature allows designers and developers to create game logic without writing the code from scratch. Some common blueprint errors include:

• Incorrect Node Connections

• Missing Variable Type

• Incorrect Variable Types

Incorrect node connections and variable mismatches are common blueprint errors, especially for those new to Unreal Engine.This happens when your blueprint nodes are not well-connected or are possibly connected to the wrong pins (input/output). To avoid these pitfalls, check out our guide on the top mistakes Unreal Engine beginners make and how to fix them.

Solutions for Blueprint Errors

• Ensure correct blueprint logic: Make sure that your blueprint logic is set up correctly and that the nodes match the correct pins. Use Unreal Engine’s debugging tools to help identify issues.

• Double-check variables: Ensure that variables are correctly defined and accessible. Missing or incorrect variables can mess with your blueprint.

General Unreal Engine Issues & Fixes

One of the most frustrating things to experience as a game designer using Unreal Engine is that it has a habit of crashing. While this Unreal Engine issue isn’t necessarily a fault on their side, it can be a nuisance but also quickly resolved because it can no longer function within its environment. Sometimes, Unreal Engine 5 optimization and adjusting Unreal Engine graphics settings can prevent crashes and other issues.

Common Causes and Fixes:

1. Unreal Engine version may need an update: Check online for the latest version and compare it with your own.

2. Your graphics card driver may need to be updated: Check the latest driver release and ensure it’s up to date.

3. You may have installed the Epic Games launcher from an incorrect file: Try reinstalling the Epic Games launcher from the official website.

4. You may have overclocked your CPU or graphics card for too long: You may have overclocked your CPU or graphics card for too long, which is a common cause of Unreal Engine 5 problems. Reset your clocking speeds or let the PC cool down.

5. Your integrated graphics card may need to be more powerful to run Unreal Engine: Try using a dedicated graphics card.

6. System files may be corrupted: Try using a system file checker to repair any corrupted files.

7. Your TDR settings may be incorrect: Try adjusting your TDR settings.

8. Third-party antivirus software may be interfering with Unreal Engine: Try disabling your antivirus software or adding Unreal Engine to its list of exceptions.

For tips on optimizing performance, especially on different hardware, check out our guide on using Unreal Engine on a cloud computer.

Additional Solutions

In addition to the solutions above, you can use software designed to optimize your PC’s performance. Instead of fully upgrading your computer to solve Unreal Engine 5 problems or dealing with Unreal Engine not working, software like Vagon helps you improve your device’s overall proficiency by running through a cloud network.

How to Uninstall Unreal Engine 5 from Epic Games

If you’re experiencing persistent Unreal Engine 5 issues and need a fresh start, you might consider uninstalling the engine. To uninstall Unreal Engine 5 from Epic Games, navigate to the Epic Games launcher, select the engine version, and click 'Uninstall.' This can resolve some Unreal Engine problems by clearing out corrupted files or incorrect installations.

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Conclusion

There is always a solution, whether you have plugin, blueprint, or shading errors. These solutions will add to your ability to self-troubleshoot so that you can get back on track designing amazing games through Unreal Engine. To further your expertise, explore our complete guide to Unreal Engine or discover the top game development companies using Unreal Engine.

FAQs

1. What are the most common Unreal Engine 5 issues?
   Some of the most frequent Unreal Engine 5 issues include crashes on startup, shader compilation errors, FPS drops, and plugin incompatibilities. Keeping your drivers updated and optimizing project settings can help resolve these problems.

2. Why is Unreal Engine not working on my PC?
   Unreal Engine not working could be due to outdated drivers, missing dependencies, or hardware limitations. Try updating Unreal Engine, checking system requirements, and verifying your installation through the Epic Games Launcher.

3. How do I fix Unreal Engine 5 crashing on startup?
   If Unreal Engine 5 keeps crashing on startup, try deleting the Saved, Intermediate, and Config folders, launching in safe mode, or running the engine with DX11 mode by adding -dx11 to the shortcut target.

4. What should I do if Unreal Engine games are not working?
   If your Unreal Engine games are not working, check for missing assets, incorrect configurations, or plugin conflicts. Ensuring all dependencies are properly imported and the build settings are correct can help fix the issue.

5. How can I improve Unreal Engine performance on a low-end PC?
   To optimize Unreal Engine on a low-end system, reduce dynamic lighting, enable Level of Detail (LOD), lower texture resolutions, and disable unnecessary post-processing effects. Alternatively, consider using Vagon’s cloud PCs for better performance.

6. How do I fix shader errors in Unreal Engine?
   Shader errors usually stem from syntax mistakes, missing dependencies, or incorrect configurations. Double-check your shader code, ensure that all required assets are loaded, and verify that your project is using the correct rendering settings.