UnkownRef Mips can cause TextureStreaming peaks during loading

UE - Rendering - Graphics Features - Mar 27, 2023

UnkownRef Mips is meant to fix/workaround the problem where some textures are used for rendering but they don't have any component references them (such as texture used by PP effects) These UnkownR ...

Open Formats: Interchange Import PIE - Importing static mesh while a PIE session is running permanently breaks nanite on the asset

UE - Editor - Open File Formats - Mar 12, 2025

Importing a Static Mesh during PIE can cause it to never enable Nanite, even if it reports that Nanite is enabled. To re-enable Nanite on the mesh, the asset needs to be deleted and imported again ...

[CrashReport] Commandlet crash - UE4Editor_Engine!FAnimationUtils::CompressAnimSequenceExplicit() [animationutils.cpp:621]

OLD - Anim - Sep 7, 2017

This is an infrequent commandlet crash that has affected a number of users exclusively in 4.17.1 (possible regression from 4.17.0?). There are also two instances of older cases in 4.13 and 4.15, bu ...

Mutable: Child parameters hidden when intermediate Object Group uses "All Options"

UE - Runtime - Mutable - Mar 31, 2026

FCustomizableInstanceDetails::FillChildrenMap() unconditionally registers parent-child relationships via __ParentParamName metadata without verifying the parent exists in the active parameter list. ...

Crash closing a project that was packaged on Windows for Linux

Tools - May 11, 2017

This occurred with both Development and DebugGame build configurations. In the game's console I tried both "quit" and "exit" and reproed the crash. The crash also occurs via Alt + F4 or closing vi ...

[CrashReport] UE4Editor_UnrealEd!UTransBuffer::Cancel() [editortransaction.cpp:697]

Tools - Nov 17, 2016

This Jira was created from CrashReports submitted by the public due to the high number of occurrences. Error message: Assertion failed: (Index >= 0) & (Index < ArrayNum) [Link Removed] [Line: 833] ...

[CrashReporter] Crash in FClassExclusionData::IsExcluded() (infinite loop)

UE - Gameplay - Aug 10, 2017

This Jira was created from CrashReports submitted by the public due to the high number of occurrences. Descriptions from users are provided below. Note: This appears to be a Commandlet crash. Erro ...

Starter Content's "P_Explosion" does not successfully convert to a Niagara System - incorrect loop, spawn, sprite size, and collision behaviors

UE - Niagara - Mar 17, 2022

Starter Content's "P_Explosion" does not successfully convert to a Niagara System - incorrect loop, spawn, sprite size, and collision behaviors Changes needed for / issues found with each emitter:A ...

CookAdditionalFilesOverride Context struct

UE - Core - Data Pipeline - Cooker - Sep 23, 2022

virtual void UObject::CookAdditionalFilesOverride allows non-package files to be copied or created during the cook whenever a UObject of your class is in a package that is cooked. This is useful for ...

AssetManager: PrimaryAssets: Allow PrimaryAssetTypesToScan entries to be extended from plugins to add directories

UE - Core - Data Pipeline - Cooker - Feb 23, 2023

Game.ini:[/Script/Engine/AssetManagerSettings]:PrimaryAssetTypes is an ini setting to specify which PrimaryAssets should be used by the engine during cook to specify which packages gets cooked and w ...