Cannot change Collision Profile of BP component instances

UE - Simulation - Physics - Oct 24, 2019

BP instances placed in level cannot have their components' collision profiles modified to anything other than default and custom. Note that this did not occur in 4.22 (after applying the separate ...

Niagara system loses source emitters when moving Engine from 4.22 or earlier to 4.23 or later.

UE - Niagara - Nov 29, 2019

The following code causes this behavior.// NiagaraSystem.cpp for (FNiagaraEmitterHandle& EmitterHandle : EmitterHandles) { EmitterHandle.ConditionalPostLoad(NiagaraVer); if (!EmitterHandl ...

Problems in skeletal mesh merge

There are a few issues a licensee has found with the skeletal mesh merge operation. See the UDN for more details and the proposed fixes. Note, the issue with the cloth merge is already logged in a ...

bIgnoreAllPressedKeysUntilRelease only applies to keys in the previous mapping

UE - Gameplay - Input - Jun 16, 2022

This is because the RebuildControlMappings function only checks this flag when you have a mapping that was already added, we should apply this for any new mappings as well.  I'll update the repro s ...

Disabling bLerpUVs in Nanite Settings of Static Mesh causes texture warping in clusters

UE - Rendering - Features - Nanite - Jan 21, 2025

The licensee has identified a potential fix by changing if( Settings.bLerpUVs ) to if( Settings.bLerpUVs || UVIndex == 0 ) On line 389 of NaniteBuilder\Private\Cluster.cpp in UE 5.5 ...

Copy-pasting custom property nodes (ControRig etc.) results in invalid bindings, perf issues

UE - ACT Character - Control Rig - Jul 28, 2025

From this UDN: [Link Removed] Suggested fix:Override PostPasteNode to perform the GUID update andAdd validation on load to strip 'invalid' copies that do not correspond to a valid pin input ...

Crash when DFAO is disabled and a lower scalability is used while Distance Field Shadowing is enabled.

UE - Graphics Features - Feb 2, 2016

When enabling Distance Fields for a project and adjusting the cvars to disable DFAO and set a lower Detail Mode will result in a crash. Using the console commands outlined in the steps will work. ...

Crash When Raycasting Against Mesh With Multiple Materials

UE - Simulation - Physics - Feb 26, 2016

When using a raycast trace against a blueprint that has a child component with multiple materials will cause the editor to crash after a few times. This will not be an instant crash, but requires th ...

Calling LoadAssetDataFromPath with default save path crashes the editor

UE - Foundation - Core - Nov 20, 2015

Attempting to call LoadAssetDataFromPath with the path set to the default save location (/Saved/SaveGames) ...

Converting Int to Byte to Enum crashes editor during PIE

UE - Gameplay - Blueprint - Jan 28, 2016

Converting Int to Byte to Enum crashes editor during PIE. Frequency: 3/3 Crashreporter: N/A ...