Unreal Engine Issues
Unreal Engine Issues
HTML5 shows up as black screen in FireFox 32-bit
UE - Platform - Mobile - Apr 16, 2015Packaged HTML5 games are not running on FireFox 32-bit Version 37.0.1; Some projects will also provide you with a scripting error that appears when you attempt to run the game on 37.0.1 Spoke with ...
Open Sound Control Blueprint Plugin stops working around 1 minute during play
UE - Audio - Jun 3, 2020Messages are not received around 1 minute into playing when using OSC blueprint plugin. Test Project: [Link Removed] User workaround: https://forums.unrealengine.com/development-discussion/blu ...
[Quartz] Play Quantized Crashes When Played On An Audio Component Spawned With 'Persist Across Level Transition'
UE - Audio - Jul 15, 2022There's a crash when "Play Quantized" is used on an Audio Component that was constructed via the functions "Create Sound 2D" or "Spawn Sound 2D" when the option 'Persist Across Level Transitions' is ...
Niagara Remove Pin Feature now deletes the variable completely from the Parameters Pane
UE - Niagara - Mar 12, 2020This is a regression from 4.24.3 (CL-11590370). Removing a pin on a Niagara Module Script parameter will removed the variable as well. This was reported and tested in 4.25 Preview 2 (CL-12055273) ...
Crash when using automated groom import
UE - Editor - Content Pipeline - Import and Export - Jan 5, 2021UDN customer reported that using automated groom import through Blueprint was crashing. This can probably be reproduced with a Python script using an asset import task with the automated flag set to ...
When ControlRig.EnableAnimNodePerformanceOptimizations is enabled, the default pose briefly appears after the Control Rig is reinitialized
UE - ACT Character - Control Rig - Sep 1, 2025Since UE5.6, ControlRig.EnableAnimNodePerformanceOptimizations is enabled by default, and this appears to be causing the issue. Specifically, when the control rig’s construction event is processed, ...
AnimNode content is not applied during PIE when s.AsyncLoadingThreadEnabled is enabled
UE - Runtime - Anim BP - Mar 16, 2026When the following setting is added to DefaultEngine.ini, the AnimNode content is not applied during PIE execution.[/Script/Engine.EditorStreamingSettings] s.AsyncLoadingThreadEnabled=True If the A ...
Drag and drop does not work from a window created with PySide
UE - Editor - Feb 5, 2026The cursor position is no longer updated during drag and drop, so drag-over events cannot respond correctly. Commenting out the following code in WindowsCursor.cpp works as a workaround ( the behavi ...
Player/Visibility Collision Doesn't Work with InstancedStaticMesh
UE - Simulation - Physics - Jul 24, 2018Player/Visibility Collision doesn't work with InstancedStaticMesh or HierarchiInstancedStaticMesh components. Found in 4.19 CL# 4033788, 4.20 CL# 4212847, 4.21 CL# 4221482 ...
Ensure fires during nativized build while packaging for any BP class based on UAnimNotify
OLD - Anim - Oct 25, 2018Cooking will fail while attempting to convert a non-data-only Blueprint class based on the native UAnimNotify class when Blueprint nativization is enabled. Workaround in lieu of a fix would be to e ...