Python crash the engine at exit.

UE - Editor - Workflow Systems - Oct 25, 2022

A UDN reported various crashes at exit in the embedded Python library. I was able to repro the issue in Release-5.1 and trace it back at the point where python runs its garbage collection in Py_Fina ...

Variant manager crash in UPropertyValue::HasValidResolve

UE - Editor - Content Pipeline - Variants - Nov 21, 2024

in the past we have reported a lot of VM related bugs which got fixed over time. Unfortunately, I think we have another one. Right now we're using 5.0.3 binaries from the launcher. Now the pro ...

Editor crash while saving asset during cook operation

UE - Foundation - Data Pipeline - Cooker - Apr 2, 2025

It is possible to experience an editor crash in 5.5.4 when the cook process generates a warning that references an asset while the editor is saving. It seems that during a save operation, the code t ...

SSR Experimental Denoiser crashes when enabled using Vulkan

UE - Graphics Features - Apr 27, 2020

Enabled the SSR Experimental Denoiser using Vulkan causes the Engine to crash. This crash does not happen with DX11 or DX12. This happens on Linux and Windows (-vulkan). This was reported and teste ...

Editor Crash when changing Default Properties of a TArray of UStucts containing an InlineEditConditionToggle property in Blueprint Parent Class

UE - Editor - Workflow Systems - Apr 5, 2024

This bug causes an editor crash. This crash occurs when changing the default values of a UStructs properties that are used as EditConditions, when they are set to InlineEditConditionToggle within a ...

Merging Splines causes Engine to Crash in 5.1

UE - World Creation - Worldbuilding Tools - Merge Actor - Dec 15, 2022

Attempting to merge two spline actors causes the Engine to crash. This issue occurs with the Steps to Reproduce regardless if there are more branches added to the tree branch spline/enabled, and reg ...

Crash when creating a Material Instance of a Material with Material Attribute Layers expression connected to a Substrate Convert Material Attributes.

UE - Rendering Architecture - Materials - Mar 8, 2025

A UDN user has reported this crash [Link Removed] The user also reports that the editor will crash:If the material is loaded while in PIE.If the material is used in a level (crash occurs when the l ...

Editor crash when building lighting and world partition minimap

UE - World Creation - Worldbuilding Tools - World Partition - Apr 17, 2025

It is possible for an editor crash to occur if a build is running (Lightmass in this case) and another is launched such as Build World Partition Minimap (as well as HLOD and Spline builders). This i ...

Editor Crash When Using FRequestPlaySessionParams GlobalMapOverride To Load World Partition Map

UE - World Creation - Worldbuilding Tools - Data Layers - Dec 6, 2024

The licensee has been using a custom CVAR to launch directly into PIE for a world partition level. Since updating to 5.4, this now causes an editor crash. The main factor appears to be whether or no ...

FTickTaskLevel::RescheduleForIntervalParallel Crash

UE - World Creation - Worldbuilding Tools - Oct 11, 2023

Short description from Licensee (attached UDN has more info):When streaming a level in and/or out (out especially in World Partition due to the bRequireFullVisibilityToRender variable usage) there i ...