Unreal Engine Issues
Unreal Engine Issues
Non-determinism in StaticMeshComponent::BodyInstance when cooking LevelInstances
UE - Simulation - Core - May 21, 2026A licensee reported that serialization of LevelSequence with StaticMeshActor with default collision for which mesh has NoCollision profile is not deterministic. The issue seems to be in the fact tha ...
Crash when saving a Data Table that is referencing itself in a Data Table Row Handle
Tools - Feb 23, 2017Crash when saving a Data Table that is referencing itself in a Data Table Row Handle. Reopening the project also causes a crash. *Regression: Yes This was fixed and working in 4.13-3037605 This i ...
Cannot debug code projects in the binary engine
UE - Foundation - Cpp Tools - UnrealBuildTool - Jun 6, 2017Code projects in the binary version of 4.16.1 cannot be launched without the Editor in the debugger in Visual Studio. The project hits a breakpoint while launching, with the following showing in the ...
Simulated physics bodies not working properly with BP Move Component To node
UE - Simulation - Physics - Jun 5, 2015This issue may reference [Link Removed] which was recently fixed with 4.9 CL-2553675. When using the MoveComponentTo node physics do not work properly compared to other methods to move a component ...
BulkData Async loading remains in memory
UE - Foundation - Core - Oct 26, 2016Gil's new loading path may already walk away from this issue. But here's some thing I tested locally if we want to fix this. A simple way to fix is to simply add BulkDataAsync.Deallocate(); ResetA ...
VC Runtime not in UnrealLightmass temp directory; causing lightmass build errors
UE - Foundation - Cpp Tools - UnrealBuildTool - Oct 14, 2015A Redistribute file for VS 2015 is needed to build lightmass, but this is not currently included with the engine. If a user does not have VS 2015 installed, lightmass will fail with this error: Un ...
Pasted material function nodes lose their connections
UE - Rendering - Architecture - Materials - Dec 3, 2019The fix for [Link Removed] caused a regression where links to material nodes no longer carry over when a group of nodes is copied and pasted ~ User submitted Image and repro steps appended. I conf ...
Android Crash on app launch if AdditionalPluginDirectories contains wildcards in path
UE - Platform - Mobile - Jun 23, 2017Having wildcards in the path for AdditionalPluginDirectories causes apps on Android to crash on launch. When testing this on iOS, the app did not crash but froze at the splash screen instead. Androi ...
Different instanced materials are seen as the same material due to GUID
UE - Graphics Features - Jun 3, 2021See licensee description of the issue: The problem appears when I have two instanced materials with the same number of parameters. I've noticed that ShaderMapId has MaterialLayersParameterIDs where ...
Invalid GUIDs on new material instance parameters cause overrides to break on base param rename
UE - Rendering - Architecture - Materials - Sep 3, 2025When a parameter value is assigned on a newly created material instance (constant or dynamic) using Set***ParameterValueInternal, the parameter’s ExpressionGUID is left invalid (0,0,0,0). Parameter ...