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 ...

Crash in AWorldDataLayers::InitializeDataLayerRuntimeStates() when quickly unloading then loading a sub-world partition

UE - World Creation - Worldbuilding Tools - Data Layers - Mar 6, 2025

From licensee: Since we integrated 5.5, we are experiencing a crash in AWorldDataLayers::InitializeDataLayerRuntimeStates() on this line check(ActiveDataLayerNames.IsEmpty() && LoadedDataLayerN ...

Landscape 'crack free displacement' option causes landscape layer coords and UVs to be wrong

UE - LD & Modeling - Terrain - Landscape - Aug 25, 2015

If you check the 'crack free displacement' option in a landscape material, it seems to break the results of both the landscape layer coords and regular UV input node. Worldposition is not affected. ...

[CrashReport] UE4Editor_UMG!TBaseDelegate<FMargin>::operator=() [delegatesignatureimpl.inl:381]

UE - Editor - UI Systems - Aug 29, 2017

This is a longstanding and common UMG crash that has affected more than 200 users since at least the 4.15 release. User DescriptionsI was working in the UI and undid several last changes in quick s ...

[CrashReport] UE4Editor_UnrealEd!FBlueprintCompileReinstancer::ReplaceInstancesOfClass_Inner() [kismetreinstanceutilities.cpp:1880]

UE - Gameplay - Blueprint Compiler - Oct 5, 2017

This is a somewhat common crash that has occurred throughout the 4.17 release. Users have not provided any description of their actions when the crash occurred. The callstack is similar to some ol ...

PakFiles: Unmounting PakFile while requests are still in progress causes assertion failure in UnMount

UE - Foundation - Mar 31, 2022

[Link Removed] Licensee is using the chunk downloader. On Shutdown method of their GameInstance, they call FChunkDownloader->Finalize. When they quit the game (Alt+F4) during a chunck download an a ...

[CrashReport] TOctree<TVolumeLightingSample<3>,FLightVolumeOctreeSemantics>::TConstElementBoxIterator<TInlineAllocator<99,FDefaultAllocator> >

UE - Graphics Features - Oct 5, 2017

This Jira is a continuation of [Link Removed]. This is the same callstack which users are submitting, however the other Jira eventually got specific repro steps which were verified fixed in 4.17.0. ...

GetPackageLengthForCooking can be much larger than the actual file path length

Tools - Jul 10, 2019

If the file path with the asset contains a project name, the cooking file pathlength is incorrectly increased. The following code in ContentBrowserUtils :: GetPackageLengthForCooking causes this is ...

Access Violation - UMovieSceneFolder::PostLoad - Accessing freed memory

UE - Anim - Sequencer - Sep 19, 2024

A licensee has hit an access violation issue due to a movie scene containing a reference to an invalid child object binding. It triggers in the following method: UMovieSceneFolder::PostLoad // Vali ...

Key precision problems on some short animations

Tools - Apr 5, 2016

Please see attached UE4_anim_interp_bug.fbx for a second example. This works as expected in 4.7 and 4.8 I've got a couple different users reporting this now. I suspected animation compression to ...