[CrashReport] UE4Editor_SlateCore!SWidget::SlatePrepass() [swidget.cpp:493]

Tools - Dec 1, 2017

This is a common crash in the 4.18 release. The callstack is rather generic, and I have attached two logs but neither displays the error information. Users have also not provided any descriptions ...

In the level editor, when configuring a component that is part of an actor blueprint, adding entries to a TMap with C++ enum keys results in duplicate keys and an incorrect warning popup.

UE - Editor - Workflow Systems - Jan 22, 2026

Note: This started happening in UE 5.4 and persists up to latest. It is probably related to [Link Removed] Closed ([Link Re ...

Crash when building lighting while in PIE

UE - Graphics Features - Feb 21, 2017

NOTE: This issue is similar to (same callstack) as [Link Removed], however this issue is still occurring in 4.15.0. Error Message: Access violation - code c0000005 (first/second chance not availab ...

[AI] EQS incorrectly sorts when auto-sort in single-item mode when there is only one filtering and one scoring test.

UE - AI - EQS - Dec 14, 2021

EQS places a cheap filter as the last step of a query when using auto-sort for single item results if there is only one filter. Found via [Link Removed] which is quoted below:Environmental Query sys ...

FBX naming conflicts causing collision to not import correctly.

UE - Editor - Content Pipeline - Import and Export - Feb 17, 2025

For our static mesh pipeline we have group nodes in Maya that use the name of the asset. Under that we have a mesh that also has the name of the asset. We may also have collision as well so a typica ...

When using Subversion (SVN) and Lock's comment is Japanese outside SourceControl, parsing of xml fails and Status may become NotControlled.

UE - Foundation - Core - Jun 28, 2019

If user lock assets with Japanese comments outside source control, XML acquired in svn status may contain Japanese strings, and XML parsing may fail and become NotControlled. This issue does not oc ...

Assertion failed: (Index >= 0) & (Index < ArrayNum) when importing large Alembic file

UE - Editor - Content Pipeline - Datasmith - Importer - May 3, 2022

Regression testing done on //UE4/Release-4.27.2 CL-18427296 and this issue did occur. [Link Removed] [Link Removed] Below is snips of customers description and proposed workaround:Importing alembi ...

[UDN - 00707230] DetailLayoutHelpers ensure when using VisibleAnywhere Instanced properties

UE - Editor - Workflow Systems - Jan 11, 2024

From UDN Description Hello, there's an ensure that's firing in `DetailLayoutHelpers.cpp#137`: [Start code block] ensure(PropertyNodeMap.ParentProperty == CurObjectNode); [End code block]when ...

StateTree: While editing State Parameters or exposed properties of a Condition/Task, an ensure() fires when editing inputs of a Property Function bound to an array element

UE - AI - StateTree - Mar 5, 2026

Consider an array property that can be edited in the StateTree editor. This can be a State Parameter or an exposed property of a Condition or Task, for example. Each element of the array can be boun ...

Wrong WPO motion vectors due to Periodic World Space node

UE - Rendering - Graphics Features - May 13, 2026

We've noticed smearing in grass due to wrong motion vectors. This appears to be caused by lack of previous frame support in the periodic world space node. This is how we fixed it: In MaterialTempl ...