Duplicating / Moving (to another level) an actor with a Hierarchical Instanced Static Mesh component causes a crash

UE - Graphics Features - Nov 14, 2016

When you have an actor with a Hierarchical Instanced Static Mesh component that has a Static Mesh set and is populated with at least 1 instance and then duplicate it or move it to another level, it ...

Open Formats: Interchange Import PIE - Importing static mesh while a PIE session is running permanently breaks nanite on the asset

UE - VEI - Open File Formats - Mar 12, 2025

Importing a Static Mesh during PIE can cause it to never enable Nanite, even if it reports that Nanite is enabled. To re-enable Nanite on the mesh, the asset needs to be deleted and imported again ...

Building for Gear VR Distribution fails due to missing Oculus lib

UE - Platform - XR - Jun 7, 2017

Users have reported that building for Distribution on Gear VR results in failure due to a missing Oculus library. The error they receive is as follows: UATHelper: Packaging (Android (ETC2)): [javac ...

bIsComposing assert with Japanese MS-IME input(candidate list related)

UE - Editor - UI Systems - Localization - Apr 18, 2017

When using MS-IME as Japanese input method, scrolling out the text field out side the view causes bIsComposing to be set false - this state causes instability of the editor. Crash happened with Win ...

CPU Collision is being offset on Z

UE - Graphics Features - Sep 29, 2014

DESCRIPTION: Collision's on CPU Particles are incorrectly being offset on Z by several units [Link Removed]https://answers.unrealengine.com/questions/105202/mesh-particle-collision-bug.html EDIT: ...

Regression: Visibility property is not seen in the animation track in UMG

UE - Anim - Sequencer - Mar 6, 2017

Visibility track in 4.15 launcher version is not visible. Converted projects from previous version which already had this track, but cannot create new one. If I add Interp keyword in the UPROPERTY, ...

iOS Device displays textures darker than in Editor

UE - Platform - Mobile - Jan 30, 2017

The issue is that on iOS devices textures are displaying significantly darker than expected. I did a color calibration with my monitor to get a more accurate representation of the texture. I set th ...

Displaying Revision control history for a file ending in an "undo" of a revision can cause a crash

UE - Editor - Jun 18, 2024

This crash is caused by how source control history is managed and shown. In this specific case the source control software is Perforce. As written in the repro steps, it can happen to any uasset tha ...

Ensure triggered in FBoundsCacheElement::GetValue when adding ISM instances in Construction Script

UE - AI - Oct 8, 2025

An ensure is triggered in FBoundsCacheElement::GetValue when adding instances to an InstancedStaticMeshComponent inside a Blueprint’s Construction Script. This occurs when the ISM component is navig ...

Update prepackaged dotnet to latest 10 patch release due to crash on Mac OS.

UE - Platform - Mac - Sep 24, 2026

A dotnet crash occurs sporadically with a sigsev or sigbus when running on Mac OS. This is in the dotnet executable itself, and can happen on commands like `dotnet build`, not just on executing the ...