Unreal Engine Issues
Unreal Engine Issues
[CrashReport] Crash on Mac related to editor close
UE - Platform - Apple - Jun 6, 2017This is a long-standing Mac crash that occurs with low frequency, but has affected more than 500 users since it started (possibly in the 4.11 release) It has recently been experienced internally by ...
Crash while scrolling through language options in Packaging settings
Tools - Jul 21, 2017This is a trending crash in the 4.17 preview. This is a regression Broken: 4.17.0-3528061 Worked: 4.16.2-3514769 User Descriptionsproject/settings/intern..language. Crashed it just by scrolling t ...
GAS and single process PIE: modifiable static variables accessed by server and client
UE - Gameplay - Gameplay Ability System - Nov 16, 2022See: UAbilitySystemGlobals::HandlePreLoadMap GAS features static variables that are modified by both server and client, thus result in issues in single process PIE where they access the same memory ...
Crash when calling SetState inside state machine OnUpdate
UE - Runtime - Anim BP - Sep 5, 2025The crash happens when SetState is called inside the function bound to OutputAnimationPose’s OnUpdate in the animation state. This way of using Set State node is the same as shown in the official do ...
Chaos Trailing Events not exposed to Blueprints and only accessible via Niagara Chaos DI
UE - Runtime - Deformable - Apr 22, 2025Chaos Trailing Events not exposed to Blueprints and only accessible via Niagara Chaos DI. The licensee noticed that the Trailing event is not available to BPs. It's expected that the same data avail ...
GeometryCache: data race between FGeometryCacheSceneProxy::CreateHitProxies and the render-thread FrameUpdate enqueued by the proxy constructor
UE - Rendering - Architecture - Oct 13, 2026Symptom An intermittent ensureMsgf fires in the editor when a level contains a UGeometryCacheComponent: Array has changed during ranged-for iteration! (TArray ranged-for iterator check, Array.h). T ...
UNetDriver server-side hitch results in ActorInfo->NextUpdateTime far into future
UE - Framework - Networking - Feb 16, 2024A high UWorld::Tick DeltaSeconds (i.e. GameThread hitch) results in a high UNetDriver::TickFlush DeltaSeconds. This DeltaSeconds can high (many seconds) if the hitch is long. This value then affects ...
The Remove-On-Break feature, set on Fracture Mode on Geometry Collections, stops shrinking and shows strange behaviors
UE - Runtime - Deformable - Oct 15, 2024The Remove-On-Break (ROB) feature, set on Fracture Mode on Geometry Collections (GC), was supposed to make the particle shrink until it vanishes. When the GC goes to sleep the shrinking stops and sh ...
[CrashReport] UE4Editor_UnrealEd!TSet<FEditorUndoClient * | SActorDetails::~SActorDetails
Tools - Sep 20, 2017This is a somewhat common crash coming out of 4.16 and 4.17. Users have not provided any description of their actions when the crash occurred. The top line of the callstack and the source context ...
FKeyHandle internal static atomic counter can overflow on long running games depending on usage pattern
UE - Runtime - Animation - Sep 24, 2025Structure FKeyHandle stores an internal index, which is initialized from a static atomic counter in the default constructor: +----- FKeyHandle::FKeyHandle() { | static std::atomic<uint32> LastKey ...