MRQ render with a slow output format drives Niagara GPU tick flush into its dummy-view path, causing an access violation in SetShaderParameters

UE - Rendering - Architecture - Niagara - Aug 18, 2026

Sorry for the AI ticket, but it did a better job than I could: Rendering a level sequence through Movie Render Queue crashes the editor with an EXCEPTION_ACCESS_VIOLATION when the scene contains a N ...

LIVE: RENDERING: Movable Mesh does not receive shadows from Static meshes in static or stationary lighting

UE - Graphics Features - Apr 30, 2014

---------------------------------------------------------------------------------------------------------------------- Build: 4.1.0-2057451 Description: Movable meshes and blueprints set to cast n ...

Crash when pressing Ctrl-Z after creating a blueprint function

UE - Gameplay - Blueprint - Feb 20, 2017

Crash when pressing Ctrl-Z after creating a blueprint function *This is a regression: Working in 4.14.3-3249277 Not working in 4.15.0-3299760* Crash Reporter: Error message: Access violation ...

Crash Occurring in FD3D11DynamicRHIModule::FindAdapter()

UE - Graphics Features - Jul 13, 2016

Error message: Assertion failed: (Index >= 0) & (Index < ArrayNum) [Link Removed] [Line: 804] Array index out of bounds: 1 from an array of size 1 Source Context: 352 353 // We a ...

"Build All Levels" does not re-AddNavigationSystemToWorld

UE - Runtime - Character - Feb 28, 2024

The Build All Levels editor action cleans up the world's NavDataSet (UNavigationSystemV1::NavDataSet) as pre-rebuild world cleanup by calling: SetNavigationSystem(nullptr); inside UWorld::Cleanu ...

Crash after setting a key on a Rotation Track, then trying to right click the key with Transform track collapsed

UE - Anim - Sequencer - Aug 3, 2016

Error message: Access violation - code c0000005 (first/second chance not available) Source Context: 336 337 if (bHasRotationKeys) 338 { 339 TSharedRef<FStru ...

Unfocused Standalone window has reduced performance

UE - Rendering - Architecture - RHI - Aug 25, 2020

User description: When I run two windowed standalone instances to test multiplayer, the unfocused window gets about 2-5 fps...but if I focus on it, smooth 120fps, yet the opposite screen is now onl ...

Incorrect behavior after attaching an actor to a non-root component of another actor in the Editor

UE - Editor - Verse Class Editor - Jul 3, 2024

UE allows actors to be attached to other actors. More precisely, it allows the root component of an actor (child) to be attached to any component of another actor (parent). From now on, "parent" and ...

Crash Clicking on Enum in BT Decorators After the Enum Has Been Altered

UE - AI - Apr 5, 2017

Clicking on a Behavior Tree decorator that references an Enum blackboard key will crash the editor if that Enum has been altered in the method described in the repro steps. If you set decorators to ...

When using Perforce, saving a level over another leaves the target umap file as "marked for delete"

UE - Editor - Mar 11, 2025

When working on a level asset and using command "File – Save Current Level As..." to save it over a different level asset, the engine first deletes the target level (that's going to be overwritten) ...