When using a hierarchy of "FilterBar.json" Editor Config files, filters added in the Editor are saved in the Engine-level file, but filters removed in the Editor are not saved anywhere

UE - Editor - Workflow Systems - Sep 13, 2023

The Editor Config system appears to support a hierarchy of JSON files (similarly to INI files) in three locations:Engine: "../../../Engine/Config/Editor"Project: "<PROJECT>/Config/Editor"User: "<APP ...

Renaming a level by WorldPartitionRenameDuplicateBuilder fails if the level contains GroupActor with non-spatial actors

UE - World Creation - Worldbuilding Tools - World Partition - Oct 24, 2023

Referece to the source level should be fixed by FReplaceObjectRefsArchive, but it is not working because ArIsModifyingWeakAndStrongReferences is not set. It can be fixed by setting the flag.class FR ...

In Standalone mode, when reading world partition actor descriptors for BP actors, "bIsSpatiallyLoaded" receives its value from the native base class instead of the BP class, so BP actors are loaded/unloaded based on the wrong condition.

UE - World Creation - Worldbuilding Tools - World Partition - Oct 15, 2024

Consider an actor defined in C++ with "bIsSpatiallyLoaded" set to true (the default), and a derived blueprint that overrides "bIsSpatiallyLoaded" to false. Now consider an actor instance of that blu ...

Content is Missing from Cook and indeterminism: StaticMeshComponents in Blueprints that copy data into themselves from StaticMesh have indeterminism due to StaticMesh not yet finished loading, postloading, or building

UE - Foundation - Nov 12, 2025

Content is Missing from Cook warnings are warnings reported at the end of cook phase of a project's data build. They report that data used by a cooked package will not be available at runtime. This ...

Mac Modern xcode framework link issue

UE - Platform - Apple - Mar 25, 2024

Our client is attempting to use an external framework as a third party within Unreal Engine, and they are encountering issues despite following the standard guidelines for adding the framework. T ...

Inconsistent parameter handling for pak/iostore block size / patch padding

UE - CoreTech - IoStore - Apr 14, 2025

Users have trouble overriding the blocksize/patchpaddingalign parameters for UnrealPak from UAT commandlines.There is no easy way to specify these parameters through a buildcookrun, instead they n ...

Missing UV Clamping or Clear in SunAlphaPS_Mobile

UE - Platform - Mobile - Nov 13, 2025

In: void SunAlphaPS_Mobile( float2 InUVs[8] : TEXCOORD0, in FStereoPSInput StereoInput, out HALF_TYPE OutColor : SV_Target0 ) { OutColor =  SunUnBias(SunShaftAndDofTexture.Sample(SunShaftAndDo ...

Gameplay Tags with the string "None" as any of its hierarchical node identifiers behave incorrectly (because of an incomplete generated FGameplayTagContainer::ParentTags array)

UE - Gameplay - Nov 19, 2024

Currently, using the string "None" as a hierarchical node identifier inside a Gameplay Tag (for example "A.B.C.None.D.E.F") is not disallowed by the engine, but results in some incorrect behaviors. ...

DataTable asset view runs out of (video) memory

UE - Editor - UI Systems - Slate - Feb 26, 2024

In some situation, Slate tries to secure incredible amount size data and run out of memory. This happens a cell having very long and complex serialized text appears on the editor and it is placed to ...

Unexpected behavior when Actor Parenting in the World Outliner of a WP map

UE - World Creation - Worldbuilding Tools - World Partition - Nov 23, 2021

Licensee reports the following in the UDN: There seems to be some other erratic behavior when using parenting in world outliner (i.e. drag and drop one actor on another one in world outliner).Since ...