Delegation issue with copied instances of a Trigger BP that is based off of the StaticMeshActor

UE - Gameplay - Blueprint - May 13, 2015

Delegation issue with copied instances of a Trigger BP that is based off of the StaticMeshActor parent class. If bp Trigger A is placed into the level and then 2 copies are made (B & C), when C i ...

Animation Orientation does not Auto-Convert to UE4 Coordinates when Reimporting

OLD - Anim - Nov 23, 2015

Animation orientation does not auto-convert to UE4 coordinates when reimporting the same way it does when importing the same animation as a new import. In other words, a run animation generated from ...

BulkData Async loading remains in memory

UE - Foundation - Core - Oct 26, 2016

Gil'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 ...

Editor reports crashes and terminates for exceptions that would otherwise be cleared by structured exception handlers

UE - Foundation - Core - CrashReportClient - Jun 8, 2020

In 4.25.1, I added a vectored exception handler to capture unhandled exceptions to the Editor process. This handler runs too soon. It doesn't let the structured exception handlers run first where ma ...

Resavepackages commandlet strips level package thumbnails

UE - Editor - May 12, 2026

When loading thumbnails in FLinkerLoad::SerializeThumbnails, the level asset has two thumbnails. The first one has a size of 0, which causes the loading process to abort early. Since the actual thum ...

"Scale for <ComponentName> has a component set to zero, which will result in a bad body instance" warning spam when moving actor instance even with Collision Profile overriden to "NoCollision"

UE - Runtime - Simulation - Jan 12, 2026

When a StaticMeshComponent has a scale component of zero in WorldSpace (after accumulating with the hierarchy from the root to it), function UPrimitiveComponent::OnCreatePhysicsState() logs the warn ...

[CrashReport] Assertion failed: NewWorld | UE4Editor_Engine!UEngine::LoadMap()

UE - Gameplay - Nov 2, 2017

This is a common and longstanding crash that has occurred since at least 4.15. Originally this was being tracked under [Link Removed] due to sharing the same callstack, but that had specific repro ...

Crash Opening Editor with Vulkan - Fatal Error - RenderingThread.cpp

UE - Rendering - Architecture - RHI - Mar 15, 2019

Editor crashes when opening to project browser on Linux. Fatal error: [File:D:\Build\++UE4\Sync\Engine\Source\Runtime\RenderCore\Private\RenderingThread.cpp] [Line: 819] Rendering thread exceptio ...

Placed level instance causes "!ActorInstanceGuid.IsValid()" assertion after changing WorldSettingsClass

UE - Engine Scaling - Streaming - Level Instances - Nov 13, 2023

Resaving the level using ResavePackagesCommandlet is a workaround. ...

Changes to Instanced Properties default value on BP not propagated to placed actors in the opened level

UE - Core - Systems - May 15, 2025

In UE versions 5.4 and onwards (as of CL 42589677 in Main), when an Instanced UObject property is defined in an Actor Blueprint, modifying the default value in the Blueprint does not propagate the c ...