Changing bIsSpatiallyLoaded can cause an Actor to be duplicated during Play-In-Editor

UE - World Creation - Worldbuilding Tools - World Partition - Dec 18, 2025

Changing bIsSpatiallyLoaded can cause an Actor to be duplicated during Play-In-Editor. As described in the steps to reproduce, if we keep swapping bIsSpatiallyLoaded state and save a Streaming Level ...

Changing the ComponentClass of a ACharacter twice and trying to set a SkeletalMeshAsset crashes the engine

UE - Runtime - Animation - Jan 22, 2026

Changing the ComponentClass of a ACharacter twice and trying to set a SkeletalMeshAsset crashes the engine with a "Cannot replace existing object of a different class" message. The conditions to re ...

GetAllocatedSize returns inaccurate number of bytes

UE - Foundation - Core - May 20, 2015

When calling GetAllocatedSize() on a TBitArray it will round down the result of MaxBits / NumBitsPerDWORD. This means that not enough bytes are allocated when the MaxBits is not divisible by NumBi ...

[CrashReport] Access violation - FLandscapeEditDataInterface::SetAlphaData()

UE - LD & Modeling - Terrain - Landscape - Jul 19, 2017

This is a common crash affecting users in 4.15 and 4.16. This callstack was previously linked to [Link Removed], but that had a specific repro case that was fixed in 4.14. Users are not providing ...

[CrashReport] Crash related to refreshing Destructible Mesh - SaveExistingSkelMeshData()

UE - Simulation - Physics - Destruction - Jul 20, 2017

This is a common crash affecting users in 4.16. User DescriptionsPressing the button to restart the basic mesh in the destruction editor causes the crash.Refreshing a Destructible Mesh that has had ...

Crash after adding an AI Perception component to a parent and child character

UE - Gameplay - Sep 14, 2017

Crash after adding an AI Perception component to a parent and child character. First they both must have had AI Perception components > Compiled and saved > Then both AI Perception components delete ...

Groom Hair Visual Issue with RBF Interpolation Enabled

UE - Graphics Features - Feb 19, 2025

When "RBF Interpolation" is enabled in the Groom settings, applying an Animation Sequence to a Skeletal Mesh that animates at a position far from the world origin causes the bound Groom shape to bec ...

LIVE: EDITOR: Extremely large trigger volumes registering overlaps multiple times upon single overlap event

UE - Simulation - Physics - Sep 9, 2014

Update: 1/27/2015 User reporting multiple overlap events/end over lap events firing on smaller triggers, their specific dimensions were 400 uu x 2000 uu on a capsule   Build: 4.4.2-2289767 Descript ...

Scene Capture 2D will default back to View 0

UE - Graphics Features - Oct 8, 2015

The scene capture will revert back to the Character BP that is placed in the level when player 2 is not moving. When they are moving the scene captuer will show correctly. You can get around this ...

Moving all the related assets to another folder at once leads to reference lost in the contents browser.

UE - Editor - Content Pipeline - Content Browser - Aug 23, 2017

Moving all the related assets into another folder leads to reference lost. This can be tested out using ShooterGame project. Also you can find materials in the skeletal mesh lost its texture. This ...