Unreal Engine Issues
Unreal Engine Issues
Unexpected behavior occurs when the default elements of a TMap in an Actor Component are modified in an instance of a Blueprint containing that Actor Component
UE - Gameplay - Blueprint - Jan 17, 2017Adding an Actor Component that contains a TMap property to a Blueprint results in unexpected behavior when default elements of the TMap are modified in an instance of the Blueprint in the level:Addi ...
World Memory Leaks crash with a hidden sublevel to a redirector
Tools - Dec 8, 2020From UDN: The reason it crashes is because Child doesn't get garbage collected, which is because it still has the RF_Standalone flag. UEditorEngine::EditorDestroyWorld clears RF_Standalone flag ...
NPC - Does not get updates from Material Parameter Collection changes in the editor
UE - Niagara - Sep 30, 2024When an MPC is selected as the Source Material Collection for an NPC, all of its current parameters are carried over to the NPC with their current values. After that, if parameters are added to, rem ...
BP compiler crash
UE - Gameplay - Blueprint Compiler - Nov 24, 2020The crash can be reproduced on the 4.26P7 or the Release4.26 stream. Following the repro steps will result in hitting the following assert: Assertion failed: !HasAnyFlags(RF_NeedLoad|RF_NeedPostLo ...
Physics simulation shows strange behavior with specific skeletal mesh configurations
UE - Simulation - Physics - Mar 3, 2017PhAT is inconsistent on when it does and doesn't apply scale to Constraint positions. This leads to cases where the positions provided create constraints that may not work when the Preview Skeletal ...
Exception on missing file during GC in horde storage
UE - Foundation - Horde - Storage - May 7, 2025During 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 ...
Conflict between sequencer transform track and Parent Constraint from the Animation Mode breaks temporary pivot translation on any actor
UE - Anim - Anim in Engine - Jul 15, 2025Note: This affects all versions from at least UE 5.3, including mainline latest. The "Animation" Editor Mode allows creating constraints for level actors. One of these, the "Parent" constraint, con ...
Project does not cook with actors containing ModularSynth component
UE - Audio - Sep 11, 2017A project does not cook with actors containing ModularSynth component. The error is a follows UATHelper: Packaging (Windows (64-bit)): Cook: LogWindows: Error: begin: stack for UAT UATHelper: Pack ...
CLONE - Project does not cook with actors containing ModularSynth component
UE - Audio - Sep 13, 2017A project does not cook with actors containing ModularSynth component. The error is a follows UATHelper: Packaging (Windows (64-bit)): Cook: LogWindows: Error: begin: stack for UAT UATHelper: Pack ...
Launch on fails during staging with a SafeCopyFile Exception for MfMedia.uplugin
Tools - Jan 10, 2017Was able to repro this on machines with and without machines set up for Xbone testing. ...