Cook non-determinism when serializing UObject pointers pointing to garbage

UE - Core - Systems - Aug 25, 2025

There's a cook determinism issue in the way UObject unversioned serialization handles UObject pointers pointing to garbage. Depending on GC timing, it can either be skipped (as a property matching C ...

Crash when building lighting while in PIE

UE - Graphics Features - Feb 21, 2017

NOTE: This issue is similar to (same callstack) as [Link Removed], however this issue is still occurring in 4.15.0. Error Message: Access violation - code c0000005 (first/second chance not availab ...

[CrashReport] Assertion failed: !bRequireNormalization - UE4Editor_Landscape!ULandscapeComponent::ReplaceLayer()

UE - LD & Modeling - Terrain - Landscape - Jul 19, 2017

This is a common crash affecting users in 4.16, and has occurred since at least 4.14. Over 200 unique users have been affected, though they have provided little information. User DescriptionsI am a ...

FBX naming conflicts causing collision to not import correctly.

UE - Editor - Content Pipeline - Import and Export - Feb 17, 2025

For our static mesh pipeline we have group nodes in Maya that use the name of the asset. Under that we have a mesh that also has the name of the asset. We may also have collision as well so a typica ...

State Tree needs to be compiled again after reopening the Project

UE - AI - StateTree - May 3, 2022

It seems upon reopening a project with State Trees, they don't always keep their last compiled state or recompile when the project is loading up. Same issue occurred when I removed a Task from a Sta ...

When importing an FBX with Combine Meshes = False, one uasset will be created for the collection of assets.

Tools - Feb 4, 2016

When importing a mesh, there is an option to Combine Meshes, which by default is checked. Unchecking this option will bring in the individually named parts contained in the FBX as unique objects in ...

Combined Translate and Rotate Mode broken when using Local Space

UE - Editor - Dec 22, 2023

From UDN: When using the Combined Translate and Rotate Mode we run into an issue where the rotation arrow moves twice as fast as the coordinate frame. The object itself rotates correctly, but if we ...

Compiling on Mac fails if build path has spaces

UE - Platform - Apple - Jan 6, 2015

UPDATE: We were able to get around this issue by renaming our external drives. The actual problem is that Mono's xbuild fails to build UnrealBuildTool QA REGRESSION: YesWORKING: 2386770BROKEN: 23 ...

[CrashReport] UE4Editor_Slate!FMenuStack::DismissInternal() [menustack.cpp:582]

UE - Editor - UI Systems - Slate - Apr 15, 2016

Error Message: Assertion failed: (Index >= 0) & (Index < ArrayNum) [Link Removed] [Line: 785] Array index out of bounds: 1 from an array of size 0 Source Context: 567 } 568 } 569 ...

[CrashReport] UE4Editor_Foliage!operator<<() [foliageinstancebase.cpp:93]

UE - World Creation - Worldbuilding Tools - Foliage - Jul 5, 2016

This Jira was created from CrashReports submitted by the public due to the high number of occurrences. Descriptions from users are provided below. Error message: Fatal error: [Link Removed] [Line: ...