Unreal Engine Issues
Unreal Engine Issues
Niagara Mesh Renderer registers NumParticles x NumMeshVariants TLAS instances
UE - Rendering - Graphics Features - Ray Tracing - May 28, 2026When using the Niagara Mesh Renderer with multiple mesh variants selected via MeshIndex, the number of TLAS instances allocated is NumParticles × NumMeshVariants and enabling the Path Tracer can ca ...
TMap where key is an FString: initializer list will accept bad MakeTuple
UE - Core - Systems - Sep 2, 2026POST LINK: https://forums.unrealengine.com/t/tmap-where-key-is-an-fstring-initializer-list-will-accept-bad-maketuple/2747443 POST BODY:Summary A TMap where the key is an FString can be created lik ...
Client Gameplay Effect stuck on due to duplicate ReplicationIDs
UE - Gameplay - Gameplay Ability System - Oct 31, 2025We've been tracking down a problem recently with the Gameplay Ability System where a gameplay effect is properly removed on the server, but the client has the gameplay effect stuck on permanently. ...
Geometry Collections built with "Use Root Proxies" rendering/transform positions ignore the original root node rotation and can lead to unexpected behaviors
UE - Runtime - Deformable - Nov 17, 2025Geometry Collections (GC) built with "Use Root Proxies" rendering/transform positions ignore the original root node rotation and can lead to unexpected behaviors. If the root node of the GC was rot ...
[AI] Gaps between Nav Mesh tiles in World Partition map causing movement issues
UE - Runtime - Character - Nov 4, 2025Navmesh has seams between some tiles that are actual edges rather than previously found "gaps" where it was a debug rendering issue. Pathfinding does fail between these tiles to go straight across. ...
[CrashReport] Mac crash - UE4Editor-Slate.dylib!FTextLayout::GetAsTextAndOffsets()
UE - Platform - Apple - Aug 15, 2017This is a trending Mac crash in 4.17.0 that also had some occurrence in 4.16. Users have not provided any descriptions of their actions when the crash occurred, but the callstack is nearly identica ...
Internal Compile error received from rearranging Format Text nodes
UE - Gameplay - Blueprint - Dec 18, 2014Internal Compile error received from rearranging Format Text nodes Output Log of Error: LogBlueprint:Error: [compiler] Error Internal compiler error inside CreateExecutionSchedule (site 2); please ...
In some situations, a Blueprint can become devoid of an Event Graph. While no graphs are present, multiple variables can be created with the same name.
UE - Framework - Blueprint Editor - Aug 26, 2024In some situations, a Blueprint can become devoid of an Event Graph, or be created without one from the start. For example, function "FKismetEditorUtilities::CreateBlueprint()" in UE 5.4 does not ca ...
Hot reload causes AnimBlueprint to lose functionality and crash
OLD - Anim - Mar 31, 2015Casting to a character class inside of AnimBlueprint after a hot reload caused editor to crash Crash Reporter: [Link Removed] Additionally, Casts fail, breaking AnimBlueprint after a hot reload ...
Hot reload causes placed actor to lose variable references
UE - Foundation - Cpp Tools - Hot Reload - Nov 9, 2017Preforming a hot reload causes placed actors to lose code based variable settings. More repro steps: 1. Open UE4Editor.exe 2. Create a First Person Code project 3. Build the project for Developme ...