Alt-tabbing out of a Standalone App or packaged version of a game does not trigger LostFocus or ReceiveFocus

Tools - Sep 9, 2015

If a user uses Alt-tab to change to another window, the ReceivedFocus and LostFocus functions are not called as they would usually be called when using something such as Shift+F1 or Ctrl+Esc. Note: ...

FIXIF: Using the Merge Blueprints feature crashes the editor

UE - Gameplay - Blueprint - Feb 18, 2015

Using the Merge Blueprints feature crashes the editor. This repro is for clicking between the error and warnings while merging, but the editor will generally crash if the Merge is finished or if an ...

Blueprints not marked dirty when variables in referenced actors are renamed

UE - Gameplay - Blueprint Compiler - Feb 20, 2018

Blueprints using renamed variable do not indicate that they need to be recompiled. (However errors are shown on play) It is possible to not see an error if you add a variable with the same name as ...

Niagara Scalability Crash When Processing Significance

UE - Niagara - Jun 4, 2025

Method FNiagaraScalabilityManager::ProcessSignificance() iterates on indices from Context.SignificanceIndices and uses them to access the State and ManagedComponents arrays. It can then decide to cr ...

Editor crashes when changing skeletal mesh if another skeletal mesh component is attached when using master pose node

OLD - Anim - Jan 27, 2020

The crash only occurs if the additional skeletal mesh component is used with Set Master Pose Component (see ToggleAttach function in the TopDownCharacter BP). It doesn't seem to matter what mesh we' ...

Set user focus for player 0 will cause other local players to lose input

UE - Gameplay - Input - Feb 28, 2019

When the player at index 0 sets its user focus it will cause other players to lose input. This does not occur when setting the user focus of players with an index higher than 0. ...

Users can create project with name of "Stack" which causes conflict with existing "Stack.h"

Tools - Sep 12, 2016

Users can create project with existing name of "Slack" which causes conflict with existing Slack.h. Call stack is log file. ...

World Source in Take Recorder does not record auto-tracked actors properly

UE - Virtual Production - Tools - Take Recorder - May 23, 2025

The Take Recorder plugin allows for multiple sources to be recorded during gameplay. The World Source is expected to record everything in the level when the Autotrack Actors option is enabled. Once ...

Crash after adding Virtual Bone, then Creating Asset

OLD - Anim - Jul 5, 2017

Occurs on? 4.16 - 3466753 - YES 4.17 - 3521650 - YES Error message: Assertion failed: RefBonePose.Num() == NumBones [Link Removed] [Line: 4400] Source Context:4387 ResetAnimation(); 4388 ...

PATH not passed to NMake script when building Android from Visual Studio

UE - Foundation - Cpp Tools - UnrealBuildTool - Jan 25, 2023

After upgrading from UE5.0.3 to UE5.1, we started seeing this error when trying to build Android Development from Visual Studio (VS2022 17.2.1): Running UnrealBuildTool: dotnet "..\..\Engine\Binari ...