Crash when using StaticDuplicateObject with mismathced Source and Destination class types

UE - Core - Systems - Jun 19, 2025

Starting in Unreal Engine 5.4, StaticDuplicateObject internally switched to using Unversioned Property Serialization (UPS) for performance reasons. However, UPS assumes the source and destination ob ...

Static mesh's material slot's cast shadow does not require a build of StaticLight

UE - Graphics Features - Dec 7, 2017

If static mesh's material slot's cast shadow is changed, UE4 does not show "LIGHTING NEEDS TO BE REBUILT". I solved it with the following fixes. StaticMeshEditorTools.cpp void FMeshSectionSettin ...

Going to an earlier point of a replay does not update to previous visibility state on an actor that was switched to not visible during demorec

UE - Networking - Jan 5, 2016

Going to an earlier point of a replay does not update to previous visibility state on an actor that was switched to not visible during demorec. Reproduced in 4.9.2 binary and Main (//UE4/Dev-Main C ...

Compiling a Blueprint that references a deleted Macro from a Custom Macro Library will crash the editor

UE - Gameplay - Blueprint - Sep 3, 2015

Compiling a Blueprint that references a deleted Macro from a Custom Macro Library will crash the editor. Crash Report: [Link Removed] This is a regression: did NOT occur in 4.8.3. Reproduced in 4. ...

Duplicate .so files in GoogleVR.

UE - Platform - XR - Jun 2, 2017

A licensee recently pointed out that there are now several GoogleVR lib files in 4.16 that are present in the Engine twice due to some of them being copied into a subdirectory. For example, , in 4.1 ...

Stencil that has been marked with ResponsiveAA is cleared by DistortionPass

UE - Rendering - Features - Dec 14, 2021

From UDN: When an object with ResponsiveAA enabled is in the screen and then an object with Distortion enabled comes into the screen, ResponsiveAA does not work. ​ I guess this is because the Ste ...

Get All Actors of Class is failing to report at Event Begin Play in a streamed level

UE - Gameplay - Sep 3, 2015

Get All Actors of Class is failing to report at Event Begin Play in a streamed level. Test project attached. This is a regression: did NOT occur in 4.8.3. Reproduced in 4.9.0 binary and Main (2678 ...

Unable to undo editing enum description

UE - Gameplay - Oct 30, 2019

The user is unable to undo the editing of the enum description. The output log and undo history would confirm that the undo was carried out, however it did not do anything in reality. Resetting the ...

Setting a component to replicate in an Actor that is already set to replicate alters the location of the mesh on the Client after enabling physics

UE - Networking - Jan 27, 2016

Setting a component to replicate in an Actor that is already set to replicate alters the location on the Client after enabling physics. Note this only appears to occur with components added in Const ...

Delay nodes occasionally don't fire the "Completed" output in a nativized build.

UE - Gameplay - Blueprint - Jun 13, 2018

This happens when the 32-bit LatentUUID signed integer that we generate for the delay node starts with "-1" when converted to an FString (e.g. "-1824950080"). During compilation, we pack latent fun ...