Changing blueprint default values inside arrays only updates loaded child blueprints

UE - CoreTech - Jul 30, 2020

The rules for delta serialization in UE4 are complicated, and the editor tries to hide them from you, which works 90% of the time but can lead to confusion and data loss in other situations. In the ...

Cannot select child anim BPs for use in linked anim layers

UE - Anim - Runtime - Jul 15, 2021

From UDN: [Link Removed] Unable to set a Child ABP with inherited interface to a Linked Animation Layer Instance Class. I have a ABP_Biped which is our main ABP. I have the locomotion (idle+straf ...

Instanced Static Meshes ignore max World Position Offset Displacement for bounds after UpdateInstanceTransform is called

UE - Graphics Features - Jun 18, 2025

When an Instanced Static Mesh Component (ISMC) uses a material with a non-zero Max World Position Offset Displacement, the bounds are correctly expanded at initialization. However, after calling Upd ...

Render target size mistmatch in ShaderDrawDebug

UE - Graphics Features - Jun 9, 2020

We found a d3d debug validation assert in RDG_EVENT_NAME("ShaderDrawDebug"), with the full DLSS integration. It however also reproduces in  (4.25.1-release, dev-rendering and the plugin branch with ...

Unwanted black boundaries are displayed in a vertical split-screen with 3 players.

UE - Gameplay - Dec 2, 2019

Floating point error from UGameViewportClient::SplitscreenInfo causes this issue. FMath::TruncToInt( 3240 /*ViewportSize*/ * 0.333f/*Ratio in SplitScreenInfo*/ ) = 1079 I suggested a following t ...

Switching a code project created in a source-built Engine to use the binary Engine results in files being deleted from the binary Engine installation

Tools - Nov 18, 2016

If a code project is created in an Engine built from source code, and then it is switched to use a binary Engine installed by the Launcher, building the project in Visual Studio will result in numer ...

5.5 Static Mesh Import Pipeline Regression

UE - Editor - Content Pipeline - Import and Export - Apr 25, 2025

This question was created in reference to: [Link Removed] This post references the first post because this problem was not discovered till now. I think it was masked because the issue appears to be ...

[CrashReport] Linux crash - FLinuxSplashState::InitSplashResources()

UE - Platform - Linux - Oct 27, 2017

This is a trending Linux crash in 4.18. It seems to occur before a project loads. Callstack from Log[2017.10.27-08.31.13:659][ 0]LogInit: - Physical RAM available (not considering process quota) ...

Crash on garbage collection - Encountered 20 object(s) breaking GC Clusters assumptions.

UE - Foundation - Core - Aug 15, 2018

Garbage collection crash during opening cinematic. Note after crashing and relaunching the game the saved file appears as 8% complete instead of 0%. Note this crash is also occurring with //UE4/D ...

Data Asset Instances created from Blueprints and are not selectable in asset pickers until their parent Blueprint is loaded. They are also not displayed correctly in the Content Browser

UE - Framework - Blueprint - Sep 3, 2024

Consider a C++/BP class containing an EditAnywhere/InstanceEditable variable with type (UDataAsset*), (UPrimaryDataAsset*), or any of their subclasses. When setting this variable using a Property Ed ...