Unreal Engine Issues
Unreal Engine Issues
Niagara system loses source emitters when moving Engine from 4.22 or earlier to 4.23 or later.
UE - Niagara - Nov 29, 2019The 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, 2022This 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, 2025The 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 ...
Poor Vulkan RHIThread performance in Development builds on some Android
UE - Platform - Mobile - Systems - Dec 10, 2024Community-attempted workaround received in [Link Removed] Closed Correct fix submitted to 5.6 FNMain in [Link Removed] whic ...
Copy-pasting custom property nodes (ControRig etc.) results in invalid bindings, perf issues
UE - ACT Character - Control Rig - Jul 28, 2025From 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 while unloading a streaming level while spawned decals exist in the unloaded level
UE - Graphics Features - Aug 18, 2017When unloading a level containing a decal that is using a dynamic material instance the editor will crash. ...
Editor crash when a Breakpoint is added to a Widget's Tick function
UE - Editor - UI Systems - Aug 18, 2017Editor crashes when a widget's tick contains a breakpoint at a print string node. Based on 4.16 warning message, this appears to be caused by the text attempting to draw when no draw buffer is avai ...
Editor crash when adding element to Instance array of custom InstanceStaticMeshComponent
UE - Gameplay - Blueprint - Sep 14, 2017Adding an instance static mesh component to a class causes the editor to crash when an instance is added to a blueprint of the class. Regression: Yes - this behavior does not occur on 4.16.3 (CL 35 ...
Editor Crashes when working in QAGame TM-Sequencer_EventTrack - TCString<TCharType>::Strlen(InName)
UE - Anim - Sequencer - Jul 12, 2017Editor Crashes when working in QAGame TM-Sequencer_EventTrack - TCString<TCharType>::Strlen(InName) This Assert happens randomly throughout the repro-steps. I am unsure what about the process cause ...