Unreal Engine Issues
Unreal Engine Issues
Content is Missing from Cook and indeterminism: StaticMeshComponents in Blueprints that copy data into themselves from StaticMesh have indeterminism due to StaticMesh not yet finished loading, postloading, or building
UE - Core - Systems - Nov 12, 2025Content is Missing from Cook warnings are warnings reported at the end of cook phase of a project's data build. They report that data used by a cooked package will not be available at runtime. This ...
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, 2026Sorry 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 ...
GeometryCache: data race between FGeometryCacheSceneProxy::CreateHitProxies and the render-thread FrameUpdate enqueued by the proxy constructor
UE - Rendering - Architecture - Oct 13, 2026Symptom An intermittent ensureMsgf fires in the editor when a level contains a UGeometryCacheComponent: Array has changed during ranged-for iteration! (TArray ranged-for iterator check, Array.h). T ...
UE4 Crashes if multiple Vive Trackers or Lighthouses are used
UE - Platform - XR - Jan 24, 2018User reports that if more than 5 trackers are connected, UE4 crashes Suggested fix: Root cause of bug is related to the fact that UE has no setup to receive input events from Vive Trackers. (we ha ...
A physics actor will still bounce if the Restitution of a Physical Matieral is set to 0
UE - Gameplay - Oct 6, 2016A physics actor will still bounce if the Restitution of a Physical Matieral is set to 0 User Description: Explanation : I am trying to create a Badminton Game for fun and while I was trying to han ...
Transform Origin Scale on the Level Sequencce Actor's Instance Data can affect rotations
zComponent - Archive - Apr 30, 2025Scale is used as part of the rotation calculation for transform multiplication, and it can have an effect in the sequence transform origins. It's expected that scale is completely ignored, and shou ...
UE4Editor_SlateCore!TSharedFromThis<SWidget,0>::AsShared() sharedpointer.h:1221
Tools - Apr 18, 2017This bug report was entered as new crash groups appeared linking to [Link Removed] which was marked as fixed for 4.15.1 and the previous reproduction did not reproduce the issue Error message: Ass ...
"Build All Levels" does not re-AddNavigationSystemToWorld
UE - Runtime - Character - Feb 28, 2024The 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 ...
[CrashReport] Assertion failed: Array index out of bounds - GetPhysicsTriMeshData() [modelcomponent.cpp:688]
UE - Simulation - Physics - Oct 30, 2017This is a semi-common crash that has occurred since at least 4.17.1. The callstack is nearly identical to [Link Removed], which was fixed in 4.18.0, however the error message and source context are ...
PCG: Unable to use Attribute property overrides to target nested struct properties, such as BodyInstance.CollisionProfileName due to how it's validated in PCGMeshSelectorByAttribute.cpp
UE - Graphics Tools - PCG - Workflow - Jun 17, 2025Context: Static Mesh Spawner is used to spawn one static mesh per point in the provided point data. PCGMeshSelectorByAttribute is used to select an entry based on an attribute present on the mesh. ...