Unreal Engine Issues
Unreal Engine Issues
Project breaks if Online Subsystem plugin is disabled
UE - Foundation - Core - Apr 25, 2017Disabling Online Subsystem prevents the project from loading. On Windows, this produces an error shown in attached screenshot. On Linux, this causes a crash with the attached callstack on project ...
Changing MaterialQualityLevel causes a crash due to a ShaderMap mismatch in UniformExpressionCache
UE - Rendering - Architecture - Materials - Nov 26, 2025A crash may occur when changing the MaterialQualitylevel via Scalability due to a race condition. The issue occurs because in ScalabilityCVarsSinkCallback(), when it creates the FGlobalComponentRec ...
Loading Duplicated Level via Python API Crashes Editor
UE - Editor - Workflow Systems - Feb 16, 2023When 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 ...
Linux: Assertion at splash screen when trying to open UE4Editor
UE - Platform - Linux - Mar 21, 2017I ran into this while looking to verify [Link Removed] at CL 3355923. I logged the issue I was verifying the fix for last night and have not updated anything locally, so the "OpenGL 4.3 not supporte ...
Crash when using a bitmap in a material.
TM - Core - Mar 3, 2025see repro steps: direct crash the material comes from FAB model: [Link Removed] ...
A Skeletal Mesh simulating physics that hits a Geometry Collection Actor with OneWayInteraction true, OneWayInteractionLevel 1, and is using Damage Propagation (default) will be accelerated so fast it immediately disappears by hitting the world limits
UE - Simulation - Core - Jan 20, 2025A Skeletal Mesh simulating physics that hits a Geometry Collection Actor with OneWayInteraction true, OneWayInteractionLevel 1, and is using Damage Propagation (default) will be accelerated so fast ...
Copying a Folder in Sequencer and later Pasting it inside Sequencer is resulting in loss of Components
UE - Anim - Sequencer - Aug 8, 2025Copying 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 ...
Editor crashes when keying a frame to an Animation from Pose with Appended Frames
UE - Anim - Runtime - May 17, 2022This 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, 2017Was able to repro this on machines with and without machines set up for Xbone testing. ...
Crash Occurs When Creating Pose Asset from an Animation in Persona
OLD - Anim - Feb 1, 2018Engine crashes when creating a new pose asset in persona using the Create Asset option -Tested with walk, idle, and run anims -Didn't crash only once out of the several times tested with the Third ...