Assertion failed: (Index >= 0) & (Index < ArrayNum) when importing large Alembic file

UE - Editor - Content Pipeline - Datasmith - Importer - May 3, 2022

Regression testing done on //UE4/Release-4.27.2 CL-18427296 and this issue did occur. [Link Removed] [Link Removed] Below is snips of customers description and proposed workaround:Importing alembi ...

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. ...

FileSystemDerivedDataBackend may output a corrupted access log

UE - Foundation - Core - Derived Data - May 20, 2021

This problem is caused by the AccessLogWriter has not been flushed at the termination. The following workaround flushes the Writer.class FFileSystemDerivedDataBackend : public FDerivedDataBackendInt ...

Crash when trimming animation and then undoing action

UE - Anim - Runtime - May 30, 2023

Repro rate: 3/3 times This is a regression as the issue does not occur in 5.1.1  ...

Machine ID is not being shown on the crashreporter website

UE - Foundation - Core - CrashReportClient - Jan 13, 2017

This is a regression from 4.14.3 ...

Exception on missing fiile during GC in horde storage

UE - Foundation - Horde - Storage - May 7, 2025

During GC, if a file was manually deleted (but the storage system is still track), GC can erroneously fail (and never remove the reference). This causes a backup in GC, putting the whole algorithm i ...

FBX: Camera imports to Matinee with skewed position and rotation

UE - Editor - Content Pipeline - Import and Export - Aug 27, 2013

Branch Build Label Changelist UE4-Main UE4_[2013-08-27_14.24] 1799942 DESCRIPTION: When importing an animated camera from Maya into Matinee, the placement of the camera is changed (shifted 90 ...

Walking into some destructibles crashes the editor

UE - Simulation - Physics - Destruction - Aug 20, 2015

Submitted by a licensee on UDN. I verified it and have attached the test level that he provided. In the test map. some boxes fall and break. Walking straight into the boxes causes the editor to cra ...

NPC - Instances does not get updates from changes to the parent Niagara Parameter Collection in the editor

UE - Niagara - Oct 4, 2024

When an Niagara Parameter Collection (NPC) is selected as the parent Collection for an NPC Instance (NPCI), all of its current parameters are carried over to the NPCI with their current values as th ...

Niagara - When Interpolated Spawning is disabled, the first frame of each particle unexpectedly does not take into account the Particle Update stage

UE - Niagara - Feb 28, 2025

Foreword: Even if the behavior described here is by design, it is rarely (if ever) expected or desired. This was discussed and agreed to be treated as a bug. Explanation below. When interpolated sp ...