OpenXR: per-frame Color/Depth mismatch caused by unsynchronized swapchain image selection across Game/Render/RHI threads (default xr.OpenXRAcquireMode=2)

UE - Platform - XR - Jul 29, 2026

Reported via UDN (case No107). Verified against //UE5/Release-5.6 sources; same code present in 5.5, 5.7, 5.8 and Main. Licensee reproduces on 5.3 and 5.6 with the Canon MREAL runtime. Symptom Fra ...

[CrashReport] Mac Metal crash - FSceneRenderer::RenderDistortion()

UE - Graphics Features - Aug 29, 2017

This is a somewhat common Mac crash occurring since 4.15 and into 4.17.1. Users have not provided any descriptions of their actions when the crash occurred. This specific callstack was previously ...

GAS: Async loaded GameplayCueNotify can execute cue events out of order

UE - Gameplay - Gameplay Ability System - Mar 22, 2025

Licensee reported problem via UDN. Context GameplayCues ('cue') are events that can be fired by game code, that are identified via a GameplayTag. Cues can be instantaneous or can be a state on any ...

[CrashReport] Linux crash - FScopeContext::FScopeContext()

UE - Platform - Linux - Oct 5, 2017

This is a somewhat common Linux crash occurring in 4.17.2. (there are a few older records in 4.16.2 and 4.17.1 also, but most occur in 4.17.2) Callstack from Log[2017.10.04-14.49.42:768][ 2]LogFi ...

[Niagara][5.8] Data Channel Read and Write register with an identical type hash when fx.Niagara.DataChannels.Enabled is set from ini, hitting checkf in FNiagaraTypeRegistry::RegisterTypeInternal

UE - Rendering - Architecture - Niagara - Sep 28, 2026

Affects: 5.8 (verified on Release-5.8), Windows, EditorSummary Adding fx.Niagara.DataChannels.Enabled=true to an ini file makes the Niagara editor assert when a Data Channel Read is created. The sa ...

Adjusting slider in Blend Space Animation causes editor to Crash

OLD - Anim - Oct 28, 2014

UPDATE: Date: 2/5/2015 Likely an instance of the same crash: [Link Removed] CrashReporter Bugg (Crash List): [Link Removed] When updating a project from UE4.4.3 to UE4.5.1 editor crashes when adju ...

[CrashReport] Mac crash - FShaderCompilingManager::ProcessCompiledShaderMaps()

UE - Graphics Features - Nov 16, 2017

This is an infrequent Mac crash in the 4.18 release. The callstack is a match to [Link Removed] (loading Zen editor on Mac), but that was confirmed fixed for 4.18.0 while this continues for users. ...

Ensure occurs when turning on Vector Fields Developer Flag

UE - Niagara - Jan 11, 2017

The editor crashes with an ensure in the output log when Vector Field flag is toggled on in the show options of the viewport. LogOutputDevice:Error: === Handled ensure: === LogOutputDevice:Error: E ...

HTML5 fails to compile on Mac/Windows - Shipping

UE - Platform - Apple - Jan 13, 2017

HTML5 fails to compile on Mac when built for shipping in binary I did not see this when packaging for development yesterday Does not occur in 4.14.3 The error appears to be WebGL relatedError: Web ...

[CrashReport] Mac crash - UE4Editor-Slate.dylib!PrepassWindowAndChildren(TSharedRef<SWindow, (ESPMode)0>)

UE - Platform - Apple - Oct 27, 2017

This Mac crash originally occurred in 4.15 around March 2017, then decreased in frequency during 4.16 and 4.17. It may be starting to trend again in 4.18. There is one record of this occurring in 4 ...