Sampling textures with bias in the path of a custom data pin causes derivative operations when avoidable

UE - Rendering Architecture - Materials - Apr 8, 2025

Materials that make use of the analytical derivatives path to avoid hardware derivatives can still generate derivative operations on texture samples when the shading model has a custom data pin and ...

Crash when calling FillDataTableFromCSVString() while viewing the contents of the data table

When the function UDataTableFunctionLibrary::FillDataTableFromCSVString() is used from Editor Utility Blueprints or Python Scripts, and the contents of the affected Data Table are currently being vi ...

Control Rig - Undo doesn't function correctly with proxy and multi bone controls

UE - Anim - Rigging - Control Rig - Oct 26, 2025

Issue from my Technical Animator where the undo operation in Control Rig doesn't work as expected on Proxy Controls. He has recreated the issue using the "Control Rig Samples Pack" and recorded a vi ...

Sub-world partitions do not properly handle partial editor loading as world partition standalone level instances' spatially loaded actors do not get loaded even when the Level Instance is force loaded or loaded in by region.

UE - World Creation - Worldbuilding Tools - World Partition - Aug 19, 2025

Context Level Instancing is a level-based workflow designed to improve and streamline the level editing experience. In a standalone Level Behavior, when the Level Instance Actor is loaded through it ...

When using object lit by the Indirect Lighting Cache sometimes the cache will not load correctly for movable objects when a level is streamed that contains a landscape

UE - LD & Modeling - Terrain - Landscape - Jun 26, 2015

When setting up a scene with a persistent level and any sublevel that contains a landscape that is loaded via load stream level node in the level BP can cause the ILC to not be correctly assigned fo ...

[CrashReport] UE4Editor_DerivedDataCache!TArray<unsigned char,FDefaultAllocator>::ResizeGrow()

UE - Graphics Features - Sep 20, 2017

This is a somewhat common crash occurring in 4.17. Users have not provided any description of their actions when the crash occurred. Source Context 165 if (GWarn) 166 { 167 ...

[CrashReport] UE4Editor_Engine!UBodySetup::FinishCreatingPhysicsMeshes() [bodysetup.cpp:464]

UE - Simulation - Physics - Oct 27, 2017

This is a trending crash coming out of the 4.18 release. User DescriptionsWas moving assets that were migrated from another project. Source Context 451 if(bClearMeshes) 452 { ...

Cannot paint landscape layers onto tiled landscapes

UE - LD & Modeling - Terrain - Landscape - Jun 30, 2015

paint layers do not take effect on all tiled layers that have a material incorporated if a user attempts to paint on them from the persistent level. ...

[CrashReport] Crash in PHAT on LeftMouse click while moving ragdoll asset during Simulate

UE - Simulation - Physics - Oct 25, 2017

Crash occurs in the updated Physics Asset Editor if you LeftClick while moving a ragdolled asset during Simulation. This is a regression from 4.17.2 User Descriptionsin the new physics asset edit ...

[CrashReport] Crash on Mac - UE4Editor-SlateCore.dylib!SWindow::IsVisible()

UE - Platform - Apple - Jun 23, 2017

This is a common crash on Mac in the 4.16 release, and has occurred with low frequency since at least 4.11. Users have not provided any descriptions, so additional information is currently unknown. ...