Packaging fails with too many instanced static meshes

UE - Graphics Features - Jun 8, 2018

Project will fail to package with more than one actor containing ISM Components. From user: "...After some testing I found that it only occurs if there are multiple actors in a map (either of the ...

Niagara Scalability Crash When Processing Significance

UE - Niagara - Jun 4, 2025

Method FNiagaraScalabilityManager::ProcessSignificance() iterates on indices from Context.SignificanceIndices and uses them to access the State and ManagedComponents arrays. It can then decide to cr ...

World Source in Take Recorder does not record auto-tracked actors properly

UE - Virtual Production - Tools - Take Recorder - May 23, 2025

The Take Recorder plugin allows for multiple sources to be recorded during gameplay. The World Source is expected to record everything in the level when the Autotrack Actors option is enabled. Once ...

Blueprint macro in a level blueprint causes memory leak

UE - Gameplay - Blueprint - Oct 15, 2019

The level blueprint has a macro that references a level. FBlueprintNodeTemplateCache keeps holding this cashe at transition level. Unable to find source-code formatter for language: text. Available ...

Crash after adding Virtual Bone, then Creating Asset

OLD - Anim - Jul 5, 2017

Occurs on? 4.16 - 3466753 - YES 4.17 - 3521650 - YES Error message: Assertion failed: RefBonePose.Num() == NumBones [Link Removed] [Line: 4400] Source Context:4387 ResetAnimation(); 4388 ...

VR Preview crash when shadow quality is set to low

UE - Platform - XR - Dec 5, 2024

[/Script/Engine.RendererSettings] r.Tonemapper.Sharpen=2 r.TemporalAA.Upsampling=False r.DefaultFeature.AutoExposure.ExtendDefaultLuminanceRange=True r.LightPropagationVolume=0 r.ReflectionCaptureRe ...

Race condition in full builds of UE4 engine source

UE - Foundation - Cpp Tools - UnrealBuildTool - Sep 26, 2019

This is a race condition caused by how "Clean.bat", a batch file used during rebuilds, tries to manually rebuild the UnrealBuildTool project when it runs. This causes a spam of UnrealBuildTool build ...

Third Person Character Package imports with linker errors

UE - Platform - XR - Oct 19, 2020

I was able to encounter these errors on the latest binary for 4.25.3 when doing a repro for a salesforce ticket. Here is the customers description:When importing the C++ ThirdPersonCharacter package ...

[CrashReport] Mac/Metal crash - Assertion failed: (PixelShader->Bindings.InOutMask

UE - Graphics Features - Nov 10, 2017

This is a low frequency but trending crash coming out of 4.18. User DescriptionsAttempting to open a copied/converted from 4.16.3 project on 4.18 preview 4. Problem arose after preview 3. Was able ...

Crash on attempt to clear(NullifyInstance) of duplicated Hierachial Instanced Static Mesh

Tools - May 31, 2019

When creating an C++ Actor with a Hierarchical Instanced Static mesh. when duplicating such an actor with mesh instances, the instances are not visible on the level. In this state, calling HISM comp ...