Crash when opening a different level after opening the preloaded level using Asset Manager

UE - Gameplay - Jan 29, 2019

After  opens the preloaded level using Asset Manager, opening another level before unloading the level will crash. Because AssetManager holds FStreamableHandle of the level, garbage collection is no ...

Array index out of range with StopTree

UE - AI - Mar 26, 2019

Crashes when exiting PIE while executing multiple async tasks. By explicitly executing EndTask and FinishAbort of RecieveAbort, this caused by performing out-of-range in array access to InstanceStac ...

Reading data back from rendertarget not working on Android opengles 3.x

UE - Platform - Mobile - Aug 7, 2019

From user: "I believe the issue is deal to the implementation of FAndroidOpenGL, there is no overriding of FOpenGL::SupportsMapBuffer(),which always return from the base FOpenGLES2 method and it is ...

XAudio2 DestroyVoice call causes significant hitching on some architectures

UE - Audio - Aug 10, 2015

Another thread: https://answers.unrealengine.com/questions/241358/amd-cpu-very-low-performance-because-ixaudio2sourc.html Note: This not a regression and has existed since our first implementation ...

Spaces are incorrectly converted to new lines when the User Header Search Paths field is populated in Xcode

UE - Platform - Apple - Feb 21, 2017

If there is a space in the name of a folder within the Engine's install path (eg. Users\Shared\Epic Games\...), the values set in the User Header Search Paths field are split into multiple lines whe ...

[ALT] - UE56 Editor launched with -AsyncLoadingThread will trigger MTAccess

UE - Core - Asset Loader - Dec 10, 2025

When launching the editor with the -AsyncLoadingThread command, the engine uses an asynchronous thread to load and instantiate UObjects. At this point, if the instantiated UObject contains an FData ...

Leaving engine open for an extremely long time builds up memory usage, eventually crashing upon any activity

Tools - May 26, 2015

Edit MattK: Not reproducible yet If the editor is open and used for a long period of time without being closed, it stores memory use. After building up a significant amount of resources building us ...

Gameplay Ability System Attribute Modifiers with a duration (including infinite) do not respect tag requirements

UE - Gameplay - Gameplay Ability System - Feb 21, 2024

When using infinite or duration-based effects, required and ignored tags will have no effect on attribute modifiers. This appears to be caused by OnAttributeAggregatorDirty (GameplayEffect.cpp:2917) ...

Post Processing Does Not Account For Screen-Percentage Quantization

UE - Graphics Features - Jul 30, 2015

When changing r.ScreenPercentage the final value used for buffer generation is clamped to the nearest 4 pixels to aid in post processing and other steps. During post processing the same calculation ...

RecastNavMesh is not generated at loaded sublevel

UE - AI - Aug 16, 2018

RecastNavMesh is not generated at the sub level dynamically added in C ++ in 4.20. In 4.18, 4.19 it was generated normally. Probably, changes to the large number about NavMesh systems from 4.19 to ...