Crash when trimming animation and then undoing action

UE - Anim - Runtime - May 30, 2023

Repro rate: 3/3 times This is a regression as the issue does not occur in 5.1.1  ...

Exception on missing fiile during GC in horde storage

UE - Foundation - Horde - Storage - May 7, 2025

During GC, if a file was manually deleted (but the storage system is still track), GC can erroneously fail (and never remove the reference). This causes a backup in GC, putting the whole algorithm i ...

NPC - Instances does not get updates from changes to the parent Niagara Parameter Collection in the editor

UE - Niagara - Oct 4, 2024

When an Niagara Parameter Collection (NPC) is selected as the parent Collection for an NPC Instance (NPCI), all of its current parameters are carried over to the NPCI with their current values as th ...

Niagara - When Interpolated Spawning is disabled, the first frame of each particle unexpectedly does not take into account the Particle Update stage

UE - Niagara - Feb 28, 2025

Foreword: Even if the behavior described here is by design, it is rarely (if ever) expected or desired. This was discussed and agreed to be treated as a bug. Explanation below. When interpolated sp ...

Option "Use Mouse for Touch" does not work correctly when running the game in "Standalone" or "New Editor Window (PIE)" modes: Virtual joystick does not appear and mouse cursor is incorrectly hidden while captured.

UE - Gameplay - Input - Apr 1, 2025

The Editor provides option "Project Settings – Engine – Input – Mouse Properties – Advanced – Use Mouse for Touch" to allow testing virtual joysticks and other touch controls with the mouse. When ru ...

When ParallelExecutor is enabled, Japanese build output of VisualStudio garbled

UE - Foundation - Cpp Tools - Sep 19, 2018

From UE4.20, Japanese build output of VisualStudio garbled. Below is a comparison between 4.19 and 4.20. ・4.19.2 1>------ すべてのリビルド開始: プロジェクト:MyProject3, 構成:Development_Editor x64 ------ 1> Clea ...

[CrashReport] FMacWindow::ApplySizeAndModeChanges | SWindow::ReshapeWindow()

UE - Platform - Apple - Dec 1, 2017

This is an infrequent Mac crash in 4.18. Users have not provided any descriptions of their actions when the crash occurred. The callstack is similar to both [Link Removed] and [Link Removed] Call ...

Attempting to build lighting in project crashes editor

UE - LD & Modeling - Terrain - Landscape - May 18, 2016

Attempting to build lighting in user's project crashes editor. Frequency: 3/3 CrashReporter: N/A ...

Crash when fast moving Character objects has Teleporting enabled

UE - Simulation - Physics - Character - Nov 28, 2022

Reproduced 3/3 times. Issue does not occur in //UE4/Release-4.27, so Confirmed Regression. ...

Editor crashes when actors using child actor component are loaded while Static mesh actor filter is enabled in the outliner

UE - Editor - Dec 5, 2022

Reproduced 3/3 times. Unclear whether this is a regression as filter GUI is new in 5.1 for Outliner. ...