[CrashReport] UE4Editor_Core!FFileHandleWindows::Seek() [windowsplatformfile.cpp:501]

UE - Foundation - Core - Aug 29, 2017

This is common crash coming out of the 4.17 and 4.18 releases. The callstack is similar to an old unresolved import crash: [Link Removed] User Descriptionsrebuilding lightbuilding lighting from a d ...

Error on Loading Pawn Blueprint Containing ActorSequenceComponent from GameMode Constructor

UE - Anim - Sequencer - Oct 25, 2017

When attempting to load a Blueprint that contains a ActorSequence component from inside of a Gamemode's constructor, errors are given. The ActorSequence component is also removed from the Blueprint ...

ProxyLOD plugin generates uninitialized vertices at end of a vertex buffer

UE - World Creation - Worldbuilding Tools - HLOD - Sep 11, 2020

ProxyLOD::FQuadricMeshSimplifier::OutputMesh may remove duped verts. The input vertex buffer was resized by numVerts from FQuadricMeshSimplifier before calling OutputMesh. So these behaviors genera ...

UMG: Drag-drop widgets get stuck at (0, 0)

UE - AI Workflows - UI Systems - UMG - Nov 7, 2022

Reported on the dev forum, drag-drop widget is broken in the 5.1 Preview.https://forums.unrealengine.com/t/unreal-engine-5-1-preview/662523/221 Anyone else having problems with UUserWidget::SetPosi ...

HLODs appear dark/near black when built for very large geometry with Virtual Textures enabled

UE - World Creation - Worldbuilding Tools - HLOD - Jan 27, 2025

Building HLODs for a very large landscape with Virtual Textures enabled results in the built HLODs being very dark for the most part. Building the same large landscape's HLODs with Virtual Textures ...

Crash When Loading Cooked Material Assets in Editor Due to Shader Serialization

UE - Rendering - Architecture - Shaders - Aug 27, 2025

In Unreal Engine 5.6+, the new shader serialization logic in FShaderMapResourceCode::Serialize does not correctly handle cooked assets that are loaded back into the editor (e.g., from a mounted .pak ...

Cooker is asserting in Class.h on UE 5.7.1

UE - Core - Systems - Dec 18, 2025

From the linked EPS case: ---------------------------- In UE 5.7 there were some changes to how Enum member names are stored. This change introduces an assert when cooking using the Editor Debug e ...

VRS Cvar Crash during CollectPSOInitializers when CVarEnableVRS.GetValueOnRenderThread() causes Ensure failure

UE - Rendering - RHI - Aug 21, 2026

We are running into an ensure that is triggered when CVarEnableVRS.GetValueOnRenderThread() is called on the game thread from FVariableRateShadingImageManager::IsAttachmentVRSEnabled. This happens ...

FPS Perf Regression on 980

UE - Graphics Features - Mar 17, 2015

At least one user has so far reported a noticeable drop in FPS from 4.6.1 to 4.7.2 in a heavy scene; using a GTX 980. I've reproduced a perf drop in a cooked 4.7 build of elemental demo compared to ...