Unreal Engine Issues
Unreal Engine Issues
Unable to launch version 4.24.1 after fresh installation. Assertionfailed IsValid()
Tools - Dec 31, 2019User is receiving a crash after a brand new installation of version 4.24.1 NOTE: User is able to launch 4.20 - 4.23.1 without issue. "I tried reinstalling the editor build, updating all of my dr ...
Unable to Import Alembic Files in UE4
UE - Editor - Content Pipeline - Import and Export - Feb 25, 2020We have written a plugin for UE4 that allows Unreal users to import and set up Megascans assets into Unreal Engine. Recently we added Alembic files to our assets and also updated all our plugins to ...
Ragdoll Physics Assets Move Sporadically After Ragdoll Physics Event Invoked
UE - Simulation - Core - May 3, 2022Occurs 3/3 times. Skeletal mesh with ragdoll physics applied exhibits sporadic motion after ragdoll physics is initiated. Regression does occur: When tested in //UE4/Release-4.27.2 @ CL18319896 n ...
Cloth environment collisions with APEX clothing is not thread safe.
UE - Simulation - Physics - Character - Jan 17, 2017This looks like a thread safety bug that's been in the clothing system for a very long time. Essentially a skeletal mesh component does a transform update and attempts to update the collisions of a ...
Crash when saving after resetting Instanced array element via Property Matrix on placed actors
UE - Editor - Workflow Systems - Nov 21, 2025When an Actor Component contains an Instanced UObject array marked EditDefaultsOnly, adding a new element to the Blueprint defaults correctly updates the Blueprint and its own Property Matrix. Howev ...
Morph target is not applied on the first frame in Level Sequence
UE - Anim - Rigging - Dec 4, 2025When a skeletal mesh with morph targets spawns in the sequence, the morph is not reflected in the first frame. In the ProcessStage_SkinCache call of SkeletalMesh, MorphVertexBuffer->SectionIds is ...
Editor crashes when Material Layer visibility is toggled after removing a Material Layer in Parent
UE - Rendering - Architecture - Materials - Jun 9, 2026When a Material Layer is removed from a Parent Material, the Parent Material updates correctly in the viewport, but any Child Material Instance do not update correctly in the viewport until the Chil ...
GPU crash dump triggered with Intel H/HX processors
TM - Rendering - Oct 3, 2024Some users have recently reported 'GPU crash dump Triggered' crashes launching, importing, or performing simple actions. Communicating with one user, general GPU TS has not helped(check for OS/drive ...
Destructible meshes always affect navigation regardless of collision
UE - AI - Jan 27, 2016Turning off a destructible mesh's collision will still affect navigation around the destructible mesh Note: This issue is related to [Link Removed]. The workaround for that issue does not apply he ...
Actor corruption due to Hierarchy broken after load
UE - World Creation - Worldbuilding Tools - World Partition - Apr 25, 2023We recently hit a situation where some actors would suddenly teleport across the map when they were modified in the editor. We figured out that the AttachParent of some actors got reset on editor l ...