BP - Nativization will fail at cook time if a BP class and a User-Defined Structure reference each other.

UE - Gameplay - Blueprint - Apr 20, 2017

Note: This happens with "Exclusive" nativization mode as well. This occurs because the nativized UDS 'GetDefaultValue()' method is generated into a .h file rather than a .cpp file. This creates a c ...

Loading Duplicated Level via Python API Crashes Editor

UE - Editor - Workflow Systems - Feb 16, 2023

When called from Python, in 5.1 the load level invocation results in a kernel panic style crash of the editor, with a message about the map leaking memory and not being able to be garbage collected ...

Performing a Hot Reload after changing a custom component code class can make the component unusable in Blueprints, or crash the Editor.

UE - Gameplay - Blueprint - Feb 19, 2015

Performing a Hot Reload after altering a custom component code class can make the component unusable in Blueprints, and even crash the Editor. WORKAROUND: Close and re-open the Editor. ...

Exiting PIE with dedicated server checked causes editor to crash on Linux

UE - Platform - Linux - Oct 25, 2016

Checking the box for Dedicated Server in the Play dropdown menu causes the editor to crash when exiting PIE. This does not occur in 4.13 or 4.14 on Windows. ...

EDITOR: CRASH: Saving a project while an auto save is occurring will crash the Editor.

Tools - Aug 1, 2014

If a user initiates a save using Ctrl+S while an autosave is in progress, the Editor will crash. CRASHREPORT: [Link Removed] ...

Copying a Folder in Sequencer and later Pasting it inside Sequencer is resulting in loss of Components

UE - Anim - Sequencer - Aug 8, 2025

Copying a Folder in Sequencer and later Pasting it inside Sequencer is resulting in loss of Components. The pasted folder is not respecting the structure that was copied. This issue only happens on ...

[AI] Crash when gathering heightfield geometry on worker thread

UE - AI - Navigation - Jun 25, 2025

From the body of the ticket: We aim to do as much of the work off the game thread as possible to avoid impacting frame rate. We've recently found a crash during collection of the geometry slices fr ...

Editor crashes when keying a frame to an Animation from Pose with Appended Frames

UE - Anim - Runtime - May 17, 2022

This is a regression. Tested in //UE4/Release-4.27 CL18319896 Editor crashes when keying a frame to an Animation from Pose with Appended Frames. ...

Launch on fails during staging with a SafeCopyFile Exception for MfMedia.uplugin

Tools - Jan 10, 2017

Was able to repro this on machines with and without machines set up for Xbone testing. ...

Crash Occurs When Actors are Attached Across Persistent and Sublevels When Levels are Saved

UE - Anim - Sequencer - Dec 12, 2017

Can attach actors to each other through the use of sequencer even though actors are in different levels which leads to crashing when saving and changing levels F3DAttachTrackEditor::IsActorPickabl ...