Enabling Merge GC Clusters and Blueprint Clustering causes a packaged Window project to crash

UE - Foundation - Core - Cooker - Jan 3, 2019

Enabling the check boxes for Merge GC Clusters and Blueprint Clustering causes packaged Windows projects to crash on startup. The log and dump files regarding this crash have been attached to this t ...

[AI] UE_MT_SCOPED_READ_ACCESS(NavElementAccessDetector) Fails in editor on fresh sync

UE - AI - Navigation - Jan 27, 2025

Licensees have reported failed multi-thread access code for NavElementAccessDetector in complex levels that have not finished compilation of their static meshes. The eventual failed check is inside ...

Sequencer Media Tracks trigger crash when an ImageSource is added

Media Framework - Jun 18, 2020

The same callstack appears in 4.24.3 (CL-11590370) but only when playing a Sequence with a Media Track that has a ImgMediaSource and Media Texture set on it. These repro steps work for 4.25 and 4.26 ...

Users project crashes when opening level that loads multiple sub-levels

UE - Foundation - Core - UObject - May 31, 2017

Users project crashes when opening level that loads multiple sub-levels. Unable to reproduce this in a clean project so the users project is provided though Epic's box account (link is in the repro ...

r.Shaders.Optimize=0 crashes when compiling a UI material

UE - Rendering Architecture - Materials - Sep 2, 2024

[2024.08.30-22.12.22:384][ 73]LogWindows: Error: appError called: Assertion failed: CurrentGPUVirtualAddress != 0 [Link Removed] [Line: 659] Disabling shader optimisation can crash the editor when ...

Compile error in ShadowDepthVertexShader.usf if INTERPOLATE_POSITION

UE - Graphics Features - Oct 21, 2015

Shader compile error in function PositionOnlyMain() in ShadowDepthVertexShader.usf if defined INTERPOLATE_POSITION. LogShaderCompilers:Warning: 1 Shader compiler errors compiling WorldGridMaterial ...

TMap does not serialize properly in specific circumstance when it contains a UObject property set to null by default

UE - Foundation - Core - Aug 8, 2018

A TMap containing a struct with a UObject reference property (set to nullptr by default) does not serialize properly for an instance where the UObject reference is set on the instance, but the TMap ...

Exporting process stuck in "Estimated time" phase when uploading projects with Panorama Sets & Presentation after freshly booting TM

TM - Core - Dec 4, 2024

Cloud Build: TWINMOTION CL app-2023.2.33001994-2024.1.37216540-2025.1.38508591-cloud-2024.12.02.095314 (DEV / STAG, CHROME) Issue: Exporting process stuck in "Estimated time" phase when uploading p ...

Assertion failed: ExportSettings == *ExistingExportSettings [File:D:\build\++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\Lightmass\Lightmass.cpp] [Line: 546]

UE - Graphics Features - Sep 12, 2023

Generated from CrashReporter Logs can be obtained via Crash Reporter ...

On static mesh import correctly named materials in project aren't automatically applied

UE - Editor - Content Pipeline - Import and Export - Jul 16, 2019

When importing a static mesh into a project with the appropriately named materials in it already they won't apply to the mesh automatically when setting Search Location to All Assets without being i ...