Crash when Live Coding is triggered after engine source edits Blueprints using ChildActorComponent

UE - Framework - Blueprint - Nov 28, 2025

After editing engine source files and triggering Live Coding, derived Blueprints that inherit from a Blueprint containing a ChildActorComponent cause UChildActorComponent::Serialize to run on a Live ...

Preview Rendering Levels Do Not Display Supported Optimization Viewmodes in Viewport Dropdown

UE - Platform - Mobile - Apr 2, 2019

When attempting to set an optimization viewmode while using a Preview Rendering Level other than Shader Model 5, the Optimization Viewmodes dropdown is missing all of its options and instead display ...

The engine crashes when adding a new brush at newly created level by a specific way.

UE - LD & Modeling - Modeling Tools - Mesh Editing - Jun 17, 2019

issuesFBSPOps::csgAddOperation returns null if BuilderBrush has no valid polys.The creating level on content browser never calls "UEditorEngine::InitBuilderBrush(NewWorld);". But "New level" button o ...

PCG sampling of RVT does only works when sampling the first texture layer

UE - World Creation - Procedural Tools - PCG Component - Dec 11, 2025

The logic for selecting a page table texture in FVirtualTexturePageTable::Initialize() uses the indexing for texture layers (index 0-7) to fetch from the page table textures (index 0-1). All RVT for ...

An imported file that resides within the project's folders gets a relative path. That path is not updated it you copy the uasset to another folder. That breaks the Reimporting functionality.

UE - Editor - Content Pipeline - Import and Export - Aug 28, 2024

An imported file that resides within the project's folders gets a relative path. That path is not updated it you copy the uasset to another folder, so from the location of the new asset's the relati ...

Crash when adding Actor Array Element to a Sequencer Event Struct

UE - Anim - Sequencer - May 25, 2017

Crash when adding Actor Array Element to a Sequencer Event Struct Error message: Assertion failed: 0 [Link Removed] [Line: 56] Source Context: 42 N = FName(*StringName); 43 ...

CreateD3D12Texture causes the Low Level Memory system to register two allocations for the same pointer on the same track channel

UE - Rendering - Architecture - RHI - Oct 31, 2024

CreateD3D12Texture causes two OnLowLevelAllocs in LLM to be called with the same pointer and the same channel, leading to a warning. LLM WARNING: Replacing allocation in tracking map. Alloc/Free Mi ...

Users can't change flags on asset entries in PSD when the asset was added via a Branch In notify

UE - Anim - Gameplay - Mar 19, 2025

Assets added to a PSD via a Branch In notify can't have their flags changed within the database. When the flags (like mirror, disable, etc) are changed, they revert back to the original value when ...

LevelEditor: "Replace Actor" marks level as dirty even when using external actors

UE - World Creation - Worldbuilding Tools - Jul 15, 2024

When using external actors, adding/removing/replacing/editing an actor instance inside a level does not cause any modification to the Level package, which helps reduce contention for the map file on ...

[CrashReport] Undo crash - FD3D11DynamicRHI::RHIDrawIndexedPrimitive() [d3d11commands.cpp:1650]

UE - Graphics Features - Nov 2, 2017

This is a trending crash coming out of 4.18, although it also occurred with less frequency in 4.16 and 4.17. The callstack shares similarities to [Link Removed] and [Link Removed], and the user com ...