This is a common crash that has occurred since at least 4.16.

The callstack is nearly identical to [Link Removed], which appears to be fixed in 4.18; and [Link Removed], which has not. The difference is that this callstack specifically references UMaterialFunctionThumbnailRenderer::Draw.

User Descriptions

  • I was in the materials editor. I had bit mask selected through the Left Click Search menu. To select the Bit Mask, I went to press "Enter"; on the numberpad, but accidently hit either the "3" key, or the "."
  • I cloned out a speed tree color variation node in a material.
  • Died when i tried to dublica lerp with ctrl-W. I am running with 4gb ram, might be why. Google chrome running in the background taking up 1gig ram

Source Context

 1638       AWorldSettings* ULevel::GetWorldSettings(bool bChecked) const
 1639       {
 1640       	if (bChecked)
 1641       	{
 1642 ***** 		checkf( WorldSettings != nullptr, *GetPathName() );
 1643       	}
 1644       	return WorldSettings;
 1645       }
Steps to Reproduce

I believe this was fixed.

Assertion failed: WorldSettings != nullptr [File:D:\Build\++UE4+Release-4.16+Compile\Sync\Engine\Source\Runtime\Engine\Private\Level.cpp] [Line: 1643] /Engine/Transient.World_7:PersistentLevel

UE4Editor_Engine!ULevel::GetWorldSettings() [level.cpp:1643]
UE4Editor_Engine!UWorld::GetWorldSettings() [world.cpp:3863]
UE4Editor_Engine!UWorld::IsPaused() [leveltick.cpp:437]
UE4Editor_Engine!UWorld::IsCameraMoveable() [leveltick.cpp:446]
UE4Editor_Engine!FSceneViewFamily::FSceneViewFamily() [sceneview.cpp:2347]
UE4Editor_UnrealEd!UMaterialFunctionThumbnailRenderer::Draw() [materialfunctionthumbnailrenderer.cpp:37]
UE4Editor_UnrealEd!ThumbnailTools::RenderThumbnail() [objecttools.cpp:3935]
UE4Editor_UnrealEd!FAssetThumbnailPool::Tick() [assetthumbnail.cpp:999]
UE4Editor_UnrealEd!FTickableEditorObject::TickObjects() [tickableeditorobject.h:21]
UE4Editor_UnrealEd!UEditorEngine::Tick() [editorengine.cpp:1400]
UE4Editor_UnrealEd!UUnrealEdEngine::Tick() [unrealedengine.cpp:386]
UE4Editor!FEngineLoop::Tick() [launchengineloop.cpp:3119]
UE4Editor!GuardedMain() [launch.cpp:166]
UE4Editor!GuardedMainWrapper() [launchwindows.cpp:134]
UE4Editor!WinMain() [launchwindows.cpp:210]
UE4Editor!__scrt_common_main_seh() [exe_common.inl:253]

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Affects Versions4.
Target Fix4.24
CreatedOct 30, 2017
ResolvedOct 29, 2019
UpdatedFeb 7, 2020
Pull Requests
4447 - klorberg