Once an actor channel is closed by NetCullDistance, root motion movement synchronization stops working

UE - Networking - Jul 12, 2021

Properties that uses DOREPLIFETIME_ACTIVE_OVERRIDE (ex. RepRootMotion ) will also skip replication when an actor channel is newly opened. This means that if the variables on the server side do not c ...

CitySample - Level MassCrowd - interactions with SmartObjects/ContextualAnimScene is broken in 5.5

UE - AI - Apr 9, 2025

The 5.5 version of the CitySample project, particularly the MassCrowd scene, was not properly maintained. The previously working functionality of NPCs being able to sit on a bench is now broken. CAS ...

Niagara color picker user parameter preview no longer updates until confirmation

UE - Niagara - Apr 18, 2025

Starting with UE 5.4, the Color Picker Tool no longer updates preview values in real time for certain editor windows like Niagara when working with User Parameters. This behavior is a regression fr ...

AnimNotify serialization crash in editor

UE - Anim - Runtime - Mar 15, 2026

The crash is caused by changing the variable type of an AnimNotify that is already referenced by a montage. This issue cannot be reproduced in 5.6. ...

Crash on iOS9 when using Apple's CFNetwork library

UE - Platform - Mobile - Dec 6, 2016

Many clients have hit a crash due to an Apple library using operator delete on a memory block that was not allocated with operator new. This happens with the following callstack on iOS9 in UE4.13 o ...

MotionWarping does not recognize new MontageInstance with the same montage

UE - Anim - Gameplay - Jan 11, 2023

When the same AnimMonotage is played again while moving with MotionWarping & RootMotion, UAnimNotifyState_MotionWarping does not recognize it. From licensee: The issue was that in URootMotionMod ...

[CrashReport] Access violation - FLandscapeEditDataInterface::SetAlphaData()

UE - LD & Modeling - Terrain - Landscape - Jul 19, 2017

This is a common crash affecting users in 4.15 and 4.16. This callstack was previously linked to [Link Removed], but that had a specific repro case that was fixed in 4.14. Users are not providing ...

Changing a Media Player asset from Stream Mode: FromURL to From Memory crashes the editor

Tools - Dec 30, 2014

Changing a Media Player asset from Stream Mode: FromURL to From Memory crashes the editor. In 4.8, the editor crashes immediately upon changing that value, with no crash report. In 4.6 and 4.7 Pre ...

[CrashReport] UE4Editor_RenderCore!FPendingCleanupObjects::FPendingCleanupObjects() [renderingthread.cpp:1151]

UE - Editor - Workflow Systems - Nov 1, 2017

This is a trending crash coming out of the 4.18 release. It may be a regression. User DescriptionsOpened the sample VR-project and entered the VR-mode form the editor.Crash in VR mode. New project ...

Crash when quick binding a function in a class that extends LevelSequenceDirector

UE - Anim - Sequencer - Sep 16, 2020

The purpose was to create a Level Sequence Director inheritance class so that the same event could be reused in multiple sequencers. Attempting to quick-bind this base Level Sequence Director event ...