Memory leak after exiting PIE

There appears to be a memory leak when you PIE and then exit PIE. Users are reporting that each time they PIE, their RAM usage jumps up, say, 10MB, then when you exit PIE, it only drops down 5MB. ...

Key precision problems on some short animations

Tools - Apr 5, 2016

Please see attached UE4_anim_interp_bug.fbx for a second example. This works as expected in 4.7 and 4.8 I've got a couple different users reporting this now. I suspected animation compression to ...

The AABBTree spatial acceleration structure goes off-sync when physics substepping is enabled in a "low" framerate environment.

UE - Runtime - Simulation - Mar 15, 2024

When you enable the physics substepping, if you run the console command p.Chaos.Solver.DebugDrawSpatialAccelerationStructure 1, you can see how does not follow the physical object. The user that rep ...

Assets with Render in Main Pass disabled show shadow artifacts

UE - Graphics Features - Apr 18, 2016

This issue was originally reported specifically for Destructibles, but it appears to affect Skeletal Meshes, and static meshes when selected. When "Render in Main Pass" has been disabled skeletal an ...

[CrashReport] UE4Editor_Engine!UGameViewportClient::Draw() [gameviewportclient.cpp:1170]

UE - Graphics Features - Apr 4, 2017

Was created from CrashReports submitted by the public due to the high number of occurrences. Descriptions from users are provided below. Error message: Access violation - code c0000005 (first/seco ...

Cook Non-Determinism in USplineComponent

UE - Editor - Feb 25, 2026

1. Non-Deterministic LastAuthority Serialization LastAuthority is assigned in USplineComponent::Serialize. Its value depends on the order in which the object and its archetype are serialized, leadi ...

Custom iOS icons don't appear on device for Windows BP projects (Binary Build)

UE - Platform - Mobile - May 4, 2018

iOS icons have stopped working for Windows BP projects again; this does not occur on Mac. It also does not occur when using a source build from p4 (only on a binary build from the launcher). Note t ...

Fail to compile with Added AIController class

UE - Foundation - Core - Jan 14, 2015

User fails to compile code template after adding AIController code to project. Regression: Not a regression happens in 4.6.1 CL-2386410 Setting up Mono Building MyProjectEditor... Compiling game m ...

[CrashReport] UE4Editor_Engine!operator new<FBatchedLine,FDefaultAllocator>() [array.h:2812]

OLD - Anim - Jun 2, 2016

Error message: Assertion failed: (Index >= 0) & (Index < ArrayNum) [Link Removed] [Line: 804] Array index out of bounds: 175 from an array of size 171 Source Context: 2797 2798 temp ...

Destructibles using Form Extended structures with rigid body collision gives wrong hit result

UE - Simulation - Physics - Destruction - Jan 7, 2015

DESCRIPTION: When using form extended structure with DMs that are hit by a rigid body the resulting hit does not reflect the correct actor if they are both using form extended. If a DM without form ...