Crash on Mac on exit.

Media Framework - Aug 17, 2020

A licensee reported trouble with a crash on exit on Mac. They discovered that the file AvfMediaPlayer.cpp, on the function Open there is this piece of code:// Force the AV player to not be able to ...

When creating a new NiagaraSystem using existing system, the DefaultEffectType set in ProjectSettings is not reflected.

UE - Niagara - Jul 24, 2023

When creating a new NiagaraSystem, the DefaultEffectType set in ProjectSettings should be reflected. If another EffectType is already set, it should be respected. The problem here is that when creat ...

GPU-ARM Mali 400 series phones will render an Opaque Unlit Material as black

UE - Platform - Mobile - Feb 12, 2016

ARM Mali 400 Series GPUs are rendering Opaque Unlit Materials as Black instead of the designated color. This is a *regression* from 4.10.2.Devices where Issue OccursDevice NameBrandBug Description ...

Misaligned sampling in UI Material with with CustomStencil

UE - Editor - UI Systems - May 19, 2025

The output of the CustomStencil node in a User Interface material does not align with the viewport dimensions. Toggling fullscreen/windowed mode (F11) causes the offset to reappear, so scaling the n ...

Regression - Nav mesh is not generated on BSP brushes after loading a map

UE - AI - Navigation - Dec 18, 2024

In UE 5.5, when loading a map and selecting "Build – Build Paths", the nav mesh is not generated on any BSP brushes (although it is correctly generated in static meshes). This did not happen in earl ...

Regression - Nav mesh is not generated on BSP brushes after loading a map

UE - AI - Navigation - Jan 14, 2025

In UE 5.5, when loading a map and selecting "Build – Build Paths", the nav mesh is not generated on any BSP brushes (although it is correctly generated in static meshes). This did not happen in earl ...

FAnimationRuntime::BlendPosesPerBoneFilter() causes an assertive crash when Skeletal Mesh LOD is changed

UE - Anim - Runtime - Nov 1, 2023

The crash occurs from "check(BoneBlendWeights.Num() == NumBones);" This crash occurs when the following conditions are met;The skeletal mesh LOD is changed.The number of bones is difference between ...

Content is Missing from Cook and indeterminism: StaticMeshComponents in Blueprints that copy data into themselves from StaticMesh have indeterminism due to StaticMesh not yet finished loading, postloading, or building

UE - Foundation - Nov 12, 2025

Content is Missing from Cook warnings are warnings reported at the end of cook phase of a project's data build. They report that data used by a cooked package will not be available at runtime. This ...

Light Function and World Position in 5.4

UE - Graphics Features - Nov 4, 2024

When rendering a Light Function into the Translucency Lighting Volume, the World Position Material Expression returns the position relative to the Camera (unrotated), not the World. This can be mor ...

Input Mapping Context entries can get into a corrupted state when swapped with another entry that has a Combo Trigger.

UE - Gameplay - Input - Aug 23, 2024

This behaviour was working correctly in version 5.3. This issue happens inside an InputMappingContext DataAsset from the EnhancedInput system. We need at least two mappings entries. One of the entri ...