Crash when calling SetState inside state machine OnUpdate

UE - Runtime - Anim BP - Sep 5, 2025

The crash happens when SetState is called inside the function bound to OutputAnimationPose’s OnUpdate in the animation state. This way of using Set State node is the same as shown in the official do ...

Visual Studio builds currently fail when a project includes a UFUNCTION with Server, Reliable, and WithValidation specifiers (with appropriate definitions in the source file).

UE - Networking - Apr 1, 2015

Using UFUNCTION(Server, Reliable, WithValidation) with an RPC function results in a failed build in Visual Studio. The same test in Main yields a different set of error messages. ...

Destructible attached with a Physics Constraint have inconsistent physics

UE - Simulation - Physics - Destruction - Jul 26, 2016

Destructible attached with a Physics Constraint have inconsistent physics compared to a standard Static Mesh. This is also sometimes prevalent with Destructibles that aren't attached with a Physics ...

Incorrect derivative ops detection when Add node is used with Nanite Pass Switch node in material graph

UE - Rendering - Features - Mar 11, 2025

Plugging an Add node which adds a constant value into a Nanite Pass switch node results in derivative ops to be detected where there should be none (which show up as red in the No Derivative Ops deb ...

Ribbon Particle Normals are reversed from default Sprite Particles

UE - Graphics Features - Oct 13, 2015

It appears that the Vertex Normals from Ribbon Particles are opposite of what is expected via the Default Particle System given both systems share the same alignment (Facing Camera) [Image Removed] ...

Packaging for DLC with plugin multiple times causes failure due to file path length

When the DLC is being built for a project and stored in a plugin, the result is normaly until the DLC is packaged multiple times. This leads to the file path becoming more and more nested each time. ...

Hot Reload Crash involving variables in USTRUCTs

UE - Foundation - Cpp Tools - Hot Reload - Sep 1, 2016

This issue was created for this UDN post: https://udn.unrealengine.com/questions/306933/hotreload-crashbad-behavior-when-addingremoving-pa.html This repro is based off his last repro, cutting it do ...

~FStaticMesh() can crash with race condition

UE - Graphics Features - Mar 21, 2017

UDN user reported frequent crashes in FStaticMesh::~FStaticMesh() on DrawListLinks[i]->Remove(false); Crash went away after adding critical sections to FStaticMesh::LinkDrawList(), FStaticMesh::Unl ...

Editor crashes when edit foliage assigned to data layer in foliage mode

UE - Engine Scaling - Streaming - Foliage - Apr 29, 2022