UMG Not working in C++, really stumped

Fixed! See here to reset visual studio project, which fixed it for me

Hey guys!

I’ve been following every tutorial on the world wide web on how to get c++ and umg working.

Here’s what I’ve done:

  • Did the whole “PublicDependencyModuleNames.AddRange(new string] { “Core”, “CoreUObject”, “Engine”, “InputCore”, “UMG”, “Slate”, “SlateCore” });” thing
  • Added all these to the project header:
    #include “Runtime/UMG/Public/UMG.h”
    #include “Runtime/UMG/Public/UMGStyle.h”
    #include “Runtime/UMG/Public/Slate/SObjectWidget.h”
    #include “Runtime/UMG/Public/IUMGModule.h”
    #include “Runtime/UMG/Public/Blueprint/UserWidget.h”
  • swung a dead cat chanting rhymes

After doing just this, everything runs. However… when I added a child class of UUserWidget, it all crashed down on me.
Basically, the engine cannot find anything beyond the “UMG/Public” folder. Anything else, such as #include “Anchors.h”, (which is found in the slate folder) cannot be registered:

*Feast your eyes on the infinite errors within the UMG.h *

Many files including userwidget have this problem.

Anyone have ideas? Im so sad I cant get it working lol!!


What is the actual error you’re getting? All your image shows is intellisense lookup failures, which happens all the time and doesn’t mean there’s any issue with the code.

The error is that it cannot find the source files, and thus it cannot compile. It cannot fine header files within these directories:


I’m assuming this means there’s nothing wrong with the code per se, but something else that has to do with external dependence directories

Ok, so when I look in the core module, I found this:

			new string] {

			new string] {

This looks like something that defines public/private folders! But UMG doesn’t have this!
Could this be the problem? If so, why am I the only one with this problem? ;_;

I can’t help you without the actual error message. Can you post the output from the visual studio build log with the error(s) in it?

Also, try omitting the full path in your includes. Instead of

#include "Runtime/UMG/Public/UMG.h"

just put

#include "UMG.h"

I’m afraid I am being very confusing.
Here’s what’s happening.

In the UMG.h, or any other header dealing with the UMG module, it has includes such as this:
#include “Anchors.h”

However, Visual Studio cannot find this file. HOWEVER If I edit the header to become this:
#include “Slate/Anchors.h”
It works. Basically, Visual Studio cannot understand that there are headers within the “Slate” directory, and all the other directories like it.
I cannot edit every single include, because each include contains more includes, and such… way too many to fix.

In other words, from what I can see every module has a list of directories to search headers for. UMG doesn’t seem to have it, for me at least.
Core does seem to have it. It looks like “PublicIncludePaths.AddRange” has something to do with this.

TL;DR: directories for includes are not known


The actual error message doesn’t do anything exciting, other than the fact that it cannot find the headers. Here’s a little example:

Error: Cannot find source file "Anchors.h"

And about the ommitting, the part I put the "#include “Runtime/UMG/Public/UMG.h” is within the project header, which everyone says to do. This part works, since it puts these files into the external dependencies folder

Okay, I’m not really sure what’s wrong. Unreal Build Tool is set up such that anything below the Public subdirectory will be found automatically without it being necessary to provide the full file path. So the fact the UMG module doesn’t specify the include paths shouldn’t be an issue.

Still a bit confused by your error message though. That came directly from the VS build output? I’ve never seen it worded that way. If you post up the entire build output, it might shed a bit more light on what’s happening.

You need to include the UMG path in your PublicIncludePaths in *.Build.cs file. After that, you should be able to include headers files in your project as usual.

As I understood it, by including a module in the public dependencies, the public include paths are set up automatically. I’ve never explicitly specified include paths for engine modules and haven’t had any problems.

Try moving the Slate and SlateCore includes from your project’s Build.cs file to a Private Dependencies line?

PublicDependencyModuleNames.AddRange(new string] { "Core", "CoreUObject", "Engine", "InputCore", "UMG" });
PrivateDependencyModuleNames.AddRange(new string] { "Slate", "SlateCore" });

Also, check your main project’s header file. Does it include Engine.h or EngineMinimal.h? Engine.h should be what you want there.

Hope those help sort things out for you!

If you could, please, elaborate on what exactly all these specifiers do, that would be great. :slight_smile:

My understanding is:

PublicIncludePaths is to allow including .h files from the **specified **module’s Public folders inside of this module’s Public folders. But since UHT parses these folders anyways you don’t really have to use this option.

*PrivateIncludePaths *is to allow including .h files from the **specified **module’s Private folders inside of this module’s Private folders, e.g. PCH header file. For instance, if I have the following folder structure:


If I add this code to SomeModule.Build.cs:

PrivateIncludePaths.AddRange(new string] { "SomeModule/Private" }

I now **can **include my SomeModulePCH.h file (because it is inside of the root Private folder, which we’ve included) inside of my Private folders, but can not include the SomeModuleOther.h since it’s in Private/Other folder which was not added to PrivateIncludePaths.

PublicDependencyModuleNames specifies modules that your** project’s or module’s Public code depends on, meaning you can include Public headers from the specified modules inside your project’s or module’s **Public **folder. It is a must when you create a new class object that inherits from objects in other modules. The most common example is UObject classes (which covers a good deal of use cases). This is why there used to be the Classes folder in the past, I guess. For instance, if I have the following folder structure:


If I add this code to MyProject.Build.cs:

PublicDependencyModuleNames.Add( "SomeModule" }

Now I can include any header file from the SomeModule’s Public folder (including sub-folders) inside of my project’s Public folder.

*PrivateDependencyModuleNames *specifies modules that your project’s or module’s Private code depends on, meaning you can include Public headers from the specified modules inside your project’s or module’s **Private **folder. You might use this when you have an interface header file in your Public folder and it’s implementation from the Private folder has several external dependencies, but the interface itself does not need to know or care about them.

If I add this code to MyProject.Build.cs:

PrivateDependencyModuleNames.Add( "SomeModule" }

Now I can include any header file from the SomeModule’s Public folder (including sub-folders) inside of my project’s Private folder.

And in general, you can not include headers from the Private folder inside of the Public folder.

Please, correct me if I am wrong. This is a tricky topic and I would love to hear the explanation from someone at Epic.

Had to make a lot of changes and fix a couple of typos. Now the information in my last post is finalized :slight_smile:

Hi, joshcamas! Have you tried the UMG C++ tutorial? It’s pretty short, code-wise, and the first two pages will have you setting up UMG and including UserWidget.h in your project. The tutorial is available here:

This tutorial should have you up and running in no time. I’ve also just tested adding a simple test UCLASS that extends UUserWidget in my local copy of that tutorial, and it compiled without issue. If it doesn’t work, please reply and we’ll figure out what’s going on in your project.

Wow guys, thanks for all the replies! :smiley: :o

@Ian: I have indeed done this, as I have followed the tutorials online :wink:
@Lauren Ridge: I’ve tried this, and it didn’t work :confused:
@Richard Hinckley: I have followed this and every other tutorial I could find, no dice :c

It looks like this could be some sort of problem with my project specifically, (visual studio, probably not ue4) somehow… something is broken in my project, for some reason! Atm I’m even more stuck due to this seemingly unrelated problem here: (If anyone knows how to fix this, I’d be happy happy xD)

I may have to be forced to create a new project and transfer stuff, which sounds very very scary… I’ve been working on this project for many months ;_; This whole thing is making me very depressed, I wanna code! :expressionless:

EDIT: I’ve noticed something new with my project: Inside the external dependencies, there’s A LOT of files… like, every single file in the entire ue4 engine. A thousand? This is new, anyone know why this is? This could be a reason.

EDIT AGAIN: In the .vcxproj file, I found a list of directories, and boom! The UMG files are indeed in there. In other words, looks like… I have to make a new project. This really sucks.


I got it working. It was something dumb having to do with the visual studio project itself. I did this to reset the vs project itself:

  • Delete the Binaries/ and Intermediate/ directories
  • Right-click my .uproject and selecting “Generate Visual Studio Files”
  • In Visual Studio, right-click my project in the Solution Explorer and select “Rebuild” with the Development Editor configuration

(Answer gotten from here)

I must say thanks to every single one of you, thank you so much for spending your valuable time helping mwa. :o :o :o

Love ya’ll!

-Josh Steinhauer

Thank you for working through this and posting the solution. I had the exact same issue. I went through the C++ UMG tutorial and everything worked perfectly. Then I added the same code to my existing project and it had the issues you were having.

Following your three steps fixed the issue. I now know to not trust the build system.

Ideally the “Refresh Visual Studio Project” command within UE4 or a similar command would do all of this for you. This is the second place I saw instructions on manually clearing out files in your UE4 folder structure to clear issues.

Does anyone know if there is a tool that will “clean” a UE4 project to fix any issues that can be introduced through tooling failures?

I found my actual issue was fixed by the following change:

#include “Engine.h”
// #include “EngineMinimal.h” 5/15/2016 due to adding UMG