Hi guys!
Today I was working on my bicycle riding simulation project, tweaking the behavior of the vehicle and messing with parameters in C++. Suddenly, after one of the launches from the project editor, it crashed. I didn’t pay much attention to it, but I remembered that the only change in the code before the crash was a replacement in the line:
float TiltVelocity = Skeleton->GetPhysicsAngularVelocityInDegrees(FName(TEXT("root"))).X;
I changed X to Y at the end.
In my opinion, this change has absolutely nothing to do with what happened (but just in case, I reverted it).
After that, I managed to launch the editor again and press “Play”. However, there was another crash. After that, Unreal Engine started crashing when trying to open the project with the error:
Fatal error: [File:D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Private\BlueprintGeneratedClass.cpp] [Line: 467] UBlueprintGeneratedClass::GetAuthoritativeClass: ClassGeneratedBy is null. class '/Game/Levels/Main/Main.Main_C'
With each attempt to open the project, this error occurred. After a few hours, I managed to change the project configuration so that another level was loaded by default. The project opened, but when trying to open the original map (named Main), Unreal Engine crashed again with the same error.
I installed “Editor Symbols for Debugging”, after which the traceback became more detailed. I carefully examined it in combination with searching online and setting breakpoints. It seems to me that the issue might be with the level file (Main.umap) itself, rather than any of the assets it loads. I moved the heaviest assets to other levels and encountered no issues.
Overall, the situation is very strange. Please help me figure it out. I can recreate the level, as there’s nothing particularly valuable in the .umap file, but I would really like to know how to address such errors in principle. I’m afraid that in the future, something like this might happen with a level that can’t be redone in just an hour.
Here’s the full traceback:
And here’s the content of the .log file:
