Template function TSparseArray::PointerToIndex does not compile

UE - Foundation - Core - May 26, 2020

Error:  C:\Program Files\Epic Games\UE_4.25\Engine\Source\Runtime\Core\Public\Containers/SparseArray.h(778): error C2440: '-': cannot convert from 'const TSparseArrayElementOrFreeListLink<TAlignedBy ...

Editor stalls on Mac after key up, mouse up

UE - Platform - Apple - Dec 19, 2019

UDN user reported a performance hit on Mac with the latest Hotfix release when the user is interacting with the editor either through keyboard or mouse input. This performance hit is noticeable whe ...

[CrashReport] FCurveEditorSharedData::FCurveEditorSharedData

UE - Niagara - Nov 1, 2017

This is a trending crash coming out of the 4.18 release. It may be a regression as there is no record of it occurring in 4.17. User Descriptionsopening a particle from the conetnt browser Source ...

Engine Crashes When Trying to Add an Entry to a TMap in a Nested Struct That is an Element of an Array

Tools - Oct 3, 2019

When trying to add an entry to a TMap in a nested struct that is an element of an array the engine crashes. This doesn't happen if it is not an array of the nested struct. Attached are .h and .cpp ...

Linked animation graph doesn't trigger anim notifications on dedicated server.

OLD - Anim - Jun 15, 2020

Linked animation graph doesn't trigger anim notifications on dedicated server. There is no expected message in log: LogBlueprintUserMessages: [HitReact_AnimBP_C_0] Client 0: HitNotify IsServer: tru ...

Ensure triggered in FBoundsCacheElement::GetValue when adding ISM instances in Construction Script

UE - AI - Oct 8, 2025

An ensure is triggered in FBoundsCacheElement::GetValue when adding instances to an InstancedStaticMeshComponent inside a Blueprint’s Construction Script. This occurs when the ISM component is navig ...

Section::TrimSection resulting in bad key values at start and end of trim range

zComponent - Archive - Dec 17, 2025

The trim process inserts keys at the start or end of the range depending if you specify Trim Left or Right, I'm finding that Trim right is inserting a key at the end of the section that is incorrect ...

Substrate Single Layer Water material fails to compile in blendable Gbuffer mode when using the Single Layer Water BSDF node

UE - Graphics Tools - Terrain - Water - Jun 16, 2026

When using Substrate in Blendable GBuffer mode, a material with the single layer water BSDF node produces a shader compiler error : MaterialEditorStats: Error: [SM6] Shader debug info dumped to: "\ ...

Crash When Opening a DataTable Based Off a Struct With a Timecode Variable

UE - Anim - Sequencer - Mar 30, 2020

When a datatable is based off a struct with a timecode variable it will crash when opening. Found in 4.24.3 CL#11590370 Reproduced in 4.23.1 CL#9631420, 4.25 Preview 4 CL#12366721, 4.26 CL#12123513 ...

VSCode finds intellisense errors in Project source files: cannot open source file "UBT_COMPILED_PLATFORM/UBT_COMPILED_PLATFORMPlatformCompilerPreSetup.h"

UE - Foundation - Cpp Tools - Jan 28, 2020

VSCode finds intellisense errors in Project source files: cannot open source file "UBT_COMPILED_PLATFORM/UBT_COMPILED_PLATFORMPlatformCompilerPreSetup.h" Similar to [Link Removed], but that was onl ...