Using the BuildGraph to create an installed binary build of the Engine will fail if Simplygon is not installed.

UE - Foundation - Horde - BuildGraph - Oct 13, 2016

A user reported that attempting to create an installed binary build of the Engine using BuildGraph will fail. This seems to be because we include the UE Simplygon implementation, but do not disable ...

DeprojectScreenPositionToWorld has inaccurate behavior in VR

UE - Platform - XR - May 6, 2015

Calling DeprojectScreenPositionToWorld while in VR mode does not project from the center of the Oculus view. Using the results of the call with a line trace will show the line coming off center fro ...

OnKeyDown does not function in packaged game

UE - Editor - UI Systems - Jul 17, 2015

Pressing down a key for a widget blueprint works in PIE however, it's not functioning once the project is packaged. Project Rar File: [Link Removed] ...

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 ...

[bug] OIT doesn't work correctly with alpha composite blend mode

UE - Rendering - Features - Shading Models - Mar 4, 2025

When using OIT, AlphaComposite Materials blend as if they are using the Translucent BlendMode. The order of macro #if … #elif cases cause AlphaComposite Materials to take the same route as Transluce ...

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 ...

Plugin dependencies causing RI parameter initialization failures (UDN)

UE - Niagara - Oct 6, 2023

Error on some Niagara emitters using the WindForce module: LogNiagaraEditor: Error: Invalid input type found while attempting initialize new rapid iteration parameters. Function Node: /Game/FX/Expl ...

[CrashReport] Assertion failed: IsValid() - UE4Editor_SlateCore!FWeakWidgetPath::GetLastWidget()

UE - Editor - UI Systems - Slate - Jun 22, 2017

This is a common crash occurring among users in the 4.16 release. Users have not provided any descriptions when they crash, so additional information is not currently available. log file attache ...

[CrashReport] UE4Editor_PropertyEditor!SDetailSingleItemRow::OnArrayDrop() [sdetailsingleitemrow.cpp:172]

Tools - Oct 10, 2017

This is a trending crash coming out of the 4.18 previews. Users have not provided any descriptions of their actions when the crash occurred. The callstack shares similarities to [Link Removed] whi ...

BlendSpace DeltaTimeRecord.Delta can incorrectly be set to zero

UE - Runtime - Animation - Apr 19, 2024

It's possible for blendspaces to end up with an invalid delta time record because of how UBlendSpace::TickAssetPlayer modifies the time record.  This only seems to happen with specific settings:Axis ...