Hi !
I’m new to Unreal Engine, and I’m currently following the tutorial of Unreal on Get Started :
I’m currently on “Code a First-Person Adventure Game”. It’s the first course using C++ classes.
I have medium-low prior knowledge on coding, mainly C# for Unity, and some other languages for work that I barely use. But almost never in C++.
All this to say that I don’t have a lot of knowledge about compiling/making build of code, it usually was quite invisible in my previous work. So I’m not confident at all about my Unreal Engine setup with Visual Studio.
So the issue I have is, when I restart my Unreal Editor for my project, my blueprint give me the message “Blueprint could not be loaded because it derives from an invalid class”.
If i Force open the blueprint, it open, but the parent c++ class is set to none.
When I try to manually reconnect it, it doesn’t appear on the list, as if it doesn’t exist.
However, the C++ Class still appear in the C++ Folder as if everything is fine.
If I delete the Blueprint, and create a new one throught this c++ class, then the blueprint work fine, until I reboot my Editor again.
Other information about the blueprint. Even when the blueprint work (So before I reboot the Editor) when I want to reference this blueprint somewhere (For exemple a GameMode in the Project Setting - Maps and Modes) then I’m looking through the list for my Blueprint, but it doesn’t appear. I have to select the blueprint in the Content Browser and use the button “Use asset selected in Content Browser” (Or something called like that) to apply it (It work fine after (Until I reboot the Editor)).
I tried with Live coding disabled, and it still didn’t worked
I tried via Building only in Unreal Engine, or building only in Visual Studio, and it still didn’t worked.
I would like to tell you all the things I tried but I tried so much different stuff in the last 2 days that I can’t remember everything, and I kinda start to be, as we say in France “Au bout du rouleau”.
An exact step-by-step things I do wich trigger the issue
- Create a new Unreal Project in 5.6
- Project is setup as “First Person-Shooter - Arena Shooter”, is setup as Blueprint-type and is called “AdventureGame”
- Then I go in Tools → Create C++ Class
- I select Game Mode Base, click Next
- Give the name “AdventureGameMode”, don’t touch Class Type, don’t touch the path and I click in Create Class
- A window pops with text “Project now includes sources, please close the editor and build from IDE” I click “Ok”
- Another window tell me that the class has been successfully added, however I must recompile the “AdventureGame” module before it appear in the Content Browser and ask me if I want to edit the code now. I click “Yes” as the Unreal course tell me to do.
- Now, Visual Studio Open. As asked by Unreal, I close the editor, I only have Visual Studio Open.
- I do Right click on Games/AdventureGame browser and build. (I’ve also tried to do build–>Build solution with same result)
- The log tell me everything as been succeded and the build is completed.
- I reopen my Project Editor
- The “C++ Classes/AdventureGame” folder exist, and the C++ class I’ve created previously is inside.
- I disable Live Coding
- Then I go on Live Coding Setting and set it as default (So Live Coding is still disabled when I open back the Editor)
- It show me 3 message in a row doing so “Are you sure you want to Update the default settings”, “The default configuration file for this setting is not currently writable. Would you like to make it writable ?” and “The default configuration file for these setting was updated succesfully. If checked into revision control this would affect other developers” I click “Yes” in the first two and “OK” on the last.
- Now I do right-Click on the C++ Class, then “Create Blueprint Class based on adventureGameMode”
- I call it BP_AdventureGameMode and put it in the folder “FirstPerson/Blueprints” then click “Create …”
- It open the Blueprint Window, the Parent Class if setup right. I save it and close it. If I open it back, it work perfectly.
- Now I do File–> Save All
- Then I close the editor, and open it back
- When I want to open the blueprint it give me this error : “Blueprint could not be loaded because it direves from an invalid class. Check to make sure the parent class for this blueprint hasn’t been removed! Do you want to continue (it can crash the editor)”
- The blueprint officially doesn’t work.
- From there if I click Yes to open the blueprint
- The blueprint open without crash
- When I go to Class Settings, Parent Class is now set to None. If I look for the C++ Class created previously, it doesn’t appear in the list to set it in Parent Class.
- However, If I go to the content browser, it’s still here.
- If I delete the Blueprint and create a new one, it will work, until I reboot the Editor etc…
For my setup :
- I got Unreal Engine 5.6 (It’s the version asked for the tutorial I follow).
- Windows 11 up to date
- Visual Studio up to date (Fresh from this afternoon, I’ve uninstall, reboot my pc then re-install everything while trying to troubleshoot the issue)
- The Windows 11 SDK is : 10.0.621.0 (I’ve put this one for my last tried cause the guy of the last tutorial I saw used this one, but I tried with many different)
Some image of my Visual Studio parameter (Sorry, it’s written in french) :
For previous attempt, I had “Unreal Engine Test Adaptater” and “Unreal Engine Installation Program” included and it still didn’t worked.
I also tried with the “Visual Studio Tools for Unreal Engine” unload as I saw on some webpage that it can cause problem with later version of the Engine (And it actually didn’t worked in my last attempt before I install it trying to fix it)
So if anyone as any idea, I’ll take it. I’m starting to think about formatting my PC at this point ^^’
Sorry for the very long message :x
EDIT :
I’ll add information that I got while I keep invastigating in my part, in case it help.
- When I reopen the editor and the blueprint don’t work, if I want to create a new blueprint, and parent my C++ class to the blueprint, it doesn’t appear on the list. However, if I create a new blueprint doing a right click on the C++ Class, and then I try parenting the C++ Class in a blueprint, it appear on the list. It dissapeared from the list when I reboot the editor.
It seems like creating a new blueprint through the C++ Class, make Unreal Engine remind that it exist.