This page is currently under construction, more errors and solutions will be added over time.

Additional Resources

Here are a few helpful guides:

This page is currently under development and will be populated as we find more common mobile development bugs/crashes. Thank you for your understanding.

If you notice a build failure in your logs, please try the following first:

Open the log that includes the information about your build failure in a text editor. This can be found in the project's directory under the Saved/Logs directory.
Use the find function (Ctrl+F) to search for the word "Error" and "Warning"
Make a list of each unique error/warning and attempt to search for other Answerhub posts that mention them (Please take a look further in this guide for more information on common error messages, as well as the information that would likely be needed to diagnose your issue)

If you cannot find another report of the error you're receiving and are not able to solve the issue, a general all purpose solution can sometimes be to delete the following folders:

Intermediate
Saved
Config

Restart your computer if there is an 'Unknown Cook Failure'

If the above does not help your situation, please look through the rest of this guide for a run down of the troubleshooting process and examples of common errors and solutions

Using Answerhub for Packaging Issues

Packaging Failed (Automation Tool Unable to Run Successfully)

The first thing to keep in mind is that there are multiple error messages that are generic that are there to let you know that a process failed but will not give any useful information otherwise. These error messages are two examples of general errors which are stating that the process failed. This could be the result of a multitude of different errors. The best course of action is to search elsewhere in the log for other errors and warnings, as this is likely a symptom of those issues.

A couple more of these types of errors are:

RunUAT.bat ERROR: AutomationTool was unable to run
Error: Error Unknown Error

Searching for your error

Once you believe you've found the actual error or warning that is causing your problem, try searching for the issue here. If the issue isn't listed on this page, you can try searching for it in our database. Try searching for your error on the Documentation page as this covers all of our support outlets.

If you are able to find a post that relates to your issue but the information is not helpful or the issue was never resolved, check the Product Version listed. If the Product Version is older than what you are currently using, create a new post (see next section). Otherwise, feel free to post about your issue on the existing page.

Posting on Answerhub

When posting about a packaging issue on Answerhub, it will be easier for someone to help you when you provide them with as much information as possible. The list below can give you a starting point but any additional information is always helpful.

Logs (These are the most important and should be attached as a .txt file)
Engine version
The exact steps you've taken to package.
The exact OS version you're on.
Can it be reproduced in a clean project?
If it can be reproduced, provide a clear list of steps to reproduce the issue.

Retrieving Logs from a packaged game

Finding errors that occur in the game that results from a successful package attempt can be done by looking at the warnings in the original packaging log but can also be seen in the logs for the packaged game itself. They can found different locations based off the platform.

Windows: PackagedDirectory/ProjectName/Saved/Logs/ProjectName.log
Mac: ~/Library/Logs/ProjectName/
iOS: Obtain logs off an iOS Device
Android: Obtain logs off an Android Device
HTML5: To be added
Linux: To be added
tvOS: To be added

What are Unreal Engine 4's system recommendations?

For developing with UE4, we recommend a certain level of hardware for a desired result. UE4 will run on desktops and laptops below these recommendations, but performance may be limited. For more information on these recommendations, please see Recommended Hardware.

Common errors

This section will provide a list of common errors along with resolved Answerhub links related to the issue as well as possible solutions.

Non-platform specific

Error loading an asset

WARNING: Visual C++ 2015 toolchain does not appear to be correctly installed. Please verify that "Common Tools for Visual C++ 2015" was selected when installing Visual Studio 2015.

No 32-bit compiler toolchain found in C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\bin\cl.exe

This is a warning that can cause other errors to occur. This can be resolved by installing the Common Tools for Visual C++ 2015 for Visual Studio 2015. Please see the Answerhub post for steps to do so.

No modules found to build. All requested binaries were already part of the installed engine data.

This is a message that points out that you are using a Plugin that requires being compiled but you're using it in a Blueprint-only project. In this case, there are three options:

Find a version of the plugin that does not require compiling, if it exists
Disable/Uninstall the plugin
Add code to your project (File > New C++ Class...). Please note: This will permanently make the project a code project.