10 or more Static Meshes set to Simulate Physics and Replicates Movement will crash the editor with PIE set to 2 or more players

UE - Networking - May 19, 2015

10 or more Static Meshes set to Simulate Physics and Replicates Movement will crash the editor with PIE set to 2 or more players. Less than 10 don't cause a crash. The user reporting this got a mor ...

[CrashReport] UE4Editor_CoreUObject!UObjectProperty::SerializeItem() [propertyobject.cpp:39]

UE - Gameplay - Blueprint - Apr 19, 2016

This Jira was created from CrashReports submitted by the public due to the high number of occurrences. Descriptions from users are provided below. Error message: Access violation - code c0000005 ( ...

BP hierarchy change triggers incorrect map actor load warning: AttachTo: '{0}' is not static {1}, cannot attach '{2}' which is static to it.

UE - Gameplay - Blueprint - Apr 11, 2024

When a blueprint's component hierarchy is changed by changing a child component's mobility value to Static while deleting its parent component which has Movable mobility, levels saved with an outdat ...

Crash when Previewing specific LODs within Static Mesh Editor at certain Screen Resolutions

Tools - Oct 27, 2016

A crash occurs when attempting to preview specific LODs when the monitor resolution forces the menu to be expanded when selecting an LOD. This Jira was created from CrashReports submitted by the pu ...

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 ...

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 ...

Paper2D performance regression due to TArray resizing

UE - Graphics Features - Aug 16, 2019

We've noticed after upgrading our heavy Paper2D project to 4.22 that tilemap performance has been massively degraded compared to previous versions. After some digging we found out that it's due to a ...

Behavior Tree (BT) services added to root nodes call the initial tick twice

UE - AI - Nov 20, 2024

Behavior Tree (BT) services added to root nodes call the initial tick twice A BT Service with the setting "Call Tick on Search Start" enabled will execute the initial tick twice when added to the ro ...

Crash when returning to viewport from immersive mode with an editor window tabbed beneath

Tools - Mar 2, 2015

When the user enters immersive mode by hitting f11 and then opens the material editor, (which opens tabbed in the editor underneath the immersive display)The engine crashes when hitting attempting t ...

BuildPatchTool crashes on Mac and Linux when building android or ios with multiple chunks

Portal - Feb 18, 2020

"It seems that deallocation of TLazySingleton<FInternationalization> causes unhandled exception. If DISABLE_LAZY_SINGLETON_DESTRUCTION=1 is provided - the build completes successfully" ...