[CrashReport] Assertion failed: NewWorld | UE4Editor_Engine!UEngine::LoadMap()

UE - Gameplay - Nov 2, 2017

This is a common and longstanding crash that has occurred since at least 4.15. Originally this was being tracked under [Link Removed] due to sharing the same callstack, but that had specific repro ...

Crash when making Android package in SlateTextShaper.cpp

UE - Editor - UI Systems - Slate - Apr 7, 2020

Crash when outputting garbled text when creating Android package. It did not occur in my colleague's environment using English OS, but occurred in my environment using Japanese OS. This issue should ...

Solidworks exporter installation does not proceed

UE - Editor - Content Pipeline - Datasmith - Exporters - Dec 9, 2021

3 users reported the same issue. DEBUG: Error 2203: Database: 1031. Cannot open database file. System error -2147287038  or DEBUG: Error 2203: Database: 1036. Cannot open database file. System err ...

Incremental Cooks: Add dependencies on files loaded during Load/Save of the package

UE - Foundation - Data Pipeline - Cooker - Oct 19, 2022

Iterative and Incremental cooking are supposed to recook packages when their "inputs" change. Most of the time inputs are the package file itself and the other package files on which it has dependen ...

[AI] BTService_RunEQS has rare crash during OnQueryFinished

UE - AI - BehaviorTree - Nov 9, 2023

The crash log shows Error: Ensure condition failed: MyMemory->RequestID != INDEX_NONE [UE5\Engine\Source\Runtime\AIModule\Private\BehaviorTree\Services\BTService_RunEQS.cpp][Line: 93]. Other logs ha ...

[DataLayer] Optimize Data Layer runtime state replication

UE - World Creation - Worldbuilding Tools - Data Layers - Dec 7, 2023

[Link Removed]This issue occurs only when I have a lot of RDLs (I tested 2500 and 1600). I tested with 6 RDLs and had no issuesI also noticed in the server log an error when a lot of RDLs are presen ...

Mesh Space Additive behave differently for non-animated bones and extra bones on a target skeleton

UE - Anim - Runtime - Dec 6, 2023

Typically, non-animated bones behave the same way as extra bones on a target skeleton. However, it appears that this isn't the case for mesh space additive sequences. When a bone is present on th ...

Changes to Instanced Properties default value on BP not propagated to placed actors in the opened level

UE - Foundation - May 15, 2025

In UE versions 5.4 and onwards (as of CL 42589677 in Main), when an Instanced UObject property is defined in an Actor Blueprint, modifying the default value in the Blueprint does not propagate the c ...

UPrimitiveComponent mouse events when underneath Slate widgets not correct

UE - Editor - UI Systems - Slate - Jan 7, 2016

Licensee is adding a widget to the viewport overlay via AddViewportWidgetContent(). The widget receives mouse input when hovered. They return unhandled from all their widget's onmouse functions and ...

Editor Crashes when importing some FBXs with multiple Material IDs in 4.14.2

UE - Editor - Content Pipeline - Import and Export - Jan 5, 2017

This is a regression in behavior between 4.14.1 and 4.14.2! The editor will crash when importing FBX meshes that have multiple material ID assignments. If it's a single material ID it will import w ...