Unreal Engine Issues
Unreal Engine Issues
Crash when opening a texture or editing its properties after stopping a preview in the material editor
UE - Rendering - Architecture - Materials - Sep 5, 2025When a texture asset has certain properties edited, its PostEditChangeProperty() method calls to UTexture::NotifyMaterials(), which triggers a recompilation of materials that reference it in their m ...
Spot Light USD Export Produces Incorrect Intensity Values Based on Cone Angle and Source Radius
UE - Editor - Content Pipeline - USD - Apr 3, 2026UPDATE: Should be fixed as of CL#52537078 (fb7af1) USD: Bake all frames of exposure animation tracks. When exporting Unreal Engine spot lights from a level to USD, lights with identical EV intensit ...
[CrashReport] Mac crash - UE4Game!FShaderCache::InternalSetGraphicsPipelineState
UE - Graphics Features - Dec 1, 2017This is a common Mac crash in 4.18. It occurs in Game mode, not in Editor. Users have not provided any descriptions of their actions when the crash occurred. Callstack from Log[2017.11.21-20.30.4 ...
Paper2D: Editor hangs when assigning Sprite Atlas Group to Sprite
UE - Gameplay - Paper2D - Dec 16, 2025In UE 5.3 and later, assigning a Sprite Atlas Group to a UPaperSprite asset can cause the editor to hang and eventually crash. This behavior has been reproduced in 5.3, 5.6, and a recent UE5-main so ...
[Stream Cache][Assert] - UnrealEditor_Engine!FCachedAudioStreamingManager::RemoveReferenceToChunk() [AudioStreamingCache.cpp:701]
UE - Audio - Mar 12, 2024Found while messing around with a revamp of some of the Audio Stream cache tests. The map in this test is a WIP as I'm still just trying stuff out, but hit this assert 5/5 times.Assertion failed: Fo ...
Crash in RHICommandContext& GetContext() in Test/Shipping builds when bUseChecksInShipping is true
UE - Rendering - Architecture - RHI - Nov 29, 2022RHIinit() calls GRHICommandList.GetImmediateCommandList().GetContext() to make sure that GDynamicRHI->Init() initialized the immediate command list (by calling FRHICommandListImmediate::InitializeIm ...
Behavior Tree (BT) services added to root nodes call the initial tick twice
UE - AI - Nov 20, 2024Behavior Tree (BT) services added to root nodes call the initial tick twice A BT Service with the setting "Call Tick on Search Start" enabled will execute the initial tick twice when added to the ro ...
FNiagaraScalabilityManager incorrectly reactivates a NiagaraComponent that was deactivated by runtime user code
UE - Niagara - Scalability - Oct 1, 2025Context: The Niagara System is the primary tool to do visual effects inside Unreal. Niagara systems can be culled due to distance. Problem: Once a deactivated Niagara System is culled due to distan ...
LevelSequenceActorSpawner::GetLevelStreaming() fails to compare sub level names when running in Pie
UE - Anim - Sequencer - Sep 26, 2019The problem is in the function with signature "ULevelStreaming* GetLevelStreaming(FString SafeLevelName, UWorld& World)" within LevelSequenceActorSpawner.cpp at line 30. The problem is with the Safe ...
Reversed Animations don't play properly using Skeletal Mesh Pose and animations with Keep State in Sequencer
UE - Anim - Sequencer - Nov 26, 2018The bug seems to only reproduce when setting animations in sequencer and only if the animations are set to "Keep state". Setting them to "restore default" makes the reversed animation play correctly ...