During SIE (simulate) and ejected-PIE, modifying a map actor causes triggers RerunConstructionScript() which discards all runtime modifications to SCS components

UE - Framework - Blueprint Runtime - Sep 6, 2024

When Simulating, or Playing-In-Editor and ejected, modifying an actor in the editor world causes the SIE/PIE runtime actor to recreate its blueprint added components via AActor::RerunConstructionScr ...

ensure(PinHelpers::UnresolvedPins.Num() == 0); fails after undoing in the editor

UE - Framework - Blueprint Editor - Sep 6, 2025

The underlying cause is some edge case involving a math expression node, which does some perhaps naive things with a contained graph. ...

Deleting transient actor marks level dirty

UE - World Creation - Worldbuilding Tools - Feb 6, 2025

The licensee has noticed that the deletion of a transient actor still marks the scene as dirty and asks it to be saved. Checking the source it was noted that the transient flag is not verified on de ...

Opening widget blueprint causes editor to crash

UE - Editor - UI Systems - Oct 17, 2014

Branch Build Label UE4-Main Promoted-CL- 2323471 DESCRIPTION: User crashes when opening a Widget blueprint.  Unable to reproduce internally. *EDIT* Repro provided by User ...

Crash when launching Google VR project

UE - Platform - XR - Dec 12, 2016

Attempting to launch a packaged Google VR game on android causes the game to crash. This has occurred on two other devices. This occurs in Main as well as Dev-VR. ...

Crash when creating StaticMesh repeatedly

Tools - Nov 21, 2014

UE4Editor crashes when creating static meshes. Event at startup time while it tries to create default object it crash sometimes. ...

Nanite Landscape crash on save

UE - Graphics Tools - Terrain - Landscape - May 21, 2024

UDN description:When landscape is flagged as Nanite enabled but nanite mesh has not been built yet, a save operation (or an auto save) triggers a fatal failed check in ULandscapeNaniteComponent::Ini ...

Crash when running "MAP REBUILD ALLVISIBLE" with hidden sublevels and then changing maps

UE - World Creation - Worldbuilding Tools - Sep 1, 2025

Running the MAP REBUILD ALLVISIBLE editor command when the current map contains hidden sublevels causes a crash upon changing maps. The issue seems to be related to hidden sublevels being cleared in ...

Build All Levels fails with duplicate level instances

UE - World Creation - Worldbuilding Tools - Level Instances - Jan 24, 2024

Adding "Add Velocity" module to event handler stage causes ensure (ensureMsg)

UE - Niagara - Scripting - Dec 19, 2023

Adding a module which has Required Dependencies (such as "Add Velocity") to event handler stage causes ensureMsg. > > In system /Game/NewNiagaraSystem.NewNiagaraSystem, module AddVelocity (NiagaraN ...