Niagara Mesh Renderer registers NumParticles x NumMeshVariants TLAS instances

UE - Rendering - Graphics Features - Ray Tracing - May 28, 2026

When using the Niagara Mesh Renderer with multiple mesh variants selected via MeshIndex, the number of TLAS instances allocated is NumParticles × NumMeshVariants and enabling the Path Tracer can ca ...

Regression: Several project settings, especially from built-in Plugins, are being silently erased when previously they were not, which is perceived as a bug

UE - Core - Systems - Feb 28, 2025

In UE's Project Settings, some pages are saved automatically to the project's "Config/Default<CATEGORY>.ini" file (meant to be version-controlled) on every change. Other pages have buttons "Set as D ...

Editor crash when a spline component is added to a blueprint and compiled

Tools - Sep 7, 2016

Most recent user affected CL: 3106830 (4.13.0) Error message: Access violation - code c0000005 (first/second chance not available) Source Context: SelectedKeys = SplineVisualizer->GetSelectedKey ...

Mobile Previewer: Safe Zone Invalid Until Window Resize

UE - Platform - Mobile - Jul 12, 2021

When the Mobile Previewer loads, the Safe Zone widget is not working properly at startup, and requires a window resize to update to the correct Safe Zone. ...

[CrashReport] UE4Editor_D3D11RHI!TerminateOnDeviceRemoved() [d3d11util.cpp:176]

UE - Graphics Features - Nov 18, 2016

Error message: Fatal error: [Link Removed] [Line: 176] Unreal Engine is exiting due to D3D device being lost. (Error: 0x887A0006 - 'HUNG') Source Context: 161 162 const TCHAR* Rea ...

[CrashReport] UE4Editor_LevelEditor!FLevelEditorActionCallbacks::Paste_CanExecute() [leveleditoractions.cpp:1602]

UE - Gameplay - Blueprint - Jan 17, 2017

This Jira was created from CrashReports submitted by the public due to the high number of occurrences. Descriptions from users are provided below. Error message: Assertion failed: GEditor->GetSele ...

Hot reload causes placed actor to lose variable references

UE - Foundation - Cpp Tools - Hot Reload - Nov 9, 2017

Preforming a hot reload causes placed actors to lose code based variable settings. More repro steps: 1. Open UE4Editor.exe 2. Create a First Person Code project 3. Build the project for Developme ...

Given specific, non consistent, network connections, replication of some data can result in incorrect values

UE - Networking - Nov 2, 2016

I appears to be possible to replicate a value and when the value gets to the client(s), it doesn't match what was sent from the server. In the project, ReplicatedActor is created by the Authority. ...

Editor crashes when using pause node in PIE while running on dedicated server

UE - Gameplay - Dec 4, 2014

If a user pauses a game while running on a dedicated server the engine will crash. Note: this crashes even when user is given an option to unpause game. Frequency: 2/2 Crash Reporter: [Link Rem ...

Editor crashes when right clicking .csv data table

UE - Gameplay - Dec 24, 2014

Right clicking a csv data table in content browser crashes editor. Frequency: 3/3 CrashReporter: [Link Removed] Callstack: MachineId:4E82586D46B558EA69EF0EAA821297B1 EpicAccountId:1558531203f8 ...