Unreal Engine Issues
Unreal Engine Issues
Displaying Revision control history for a file ending in an "undo" of a revision can cause a crash
UE - Editor - Workflow Systems - Jun 18, 2024This crash is caused by how source control history is managed and shown. In this specific case the source control software is Perforce. As written in the repro steps, it can happen to any uasset tha ...
Ensure triggered in FBoundsCacheElement::GetValue when adding ISM instances in Construction Script
UE - AI - Oct 8, 2025An ensure is triggered in FBoundsCacheElement::GetValue when adding instances to an InstancedStaticMeshComponent inside a Blueprint’s Construction Script. This occurs when the ISM component is navig ...
Sampling Scene Texture in Custom Expression in Post Process Material Breaks Viewport UV
UE - Graphics Features - Apr 6, 2018This issue does not occur in 4.18.3 but does occur in 4.19 and Main, making this a regression. Per user: I suspect there's an issue with custom expressions and sampling coordinates. It appears onc ...
[CrashReport] UE4Editor_BlueprintGraph!BlueprintActionFilterImpl::IsEventUnimplementable() [blueprintactionfilter.cpp:588]
UE - Gameplay - Blueprint - Jun 1, 2016This crash has been reported through the 4.12 Previews and is continuing to occur in the 4.12.0 release. Additional information about this crash is not available at this time, however it may be the ...
The FNetNameMapping::GetUniqueName function appends numerical values to the end of the previous name instead of replacing the previous name's numerical value
UE - Gameplay - Blueprint Compiler - Feb 23, 2018The GetUniqueName() function attempts to make sure that all node names are unique. For nodes that are used a large number of times, it adds a numerical value to the end of the name. Prior to 4.18, t ...
ModularGameplay and other runtime plugins have wrong LoadingPhase
UE - Gameplay - Jun 30, 2022Plugins that provide blueprint-accessible libraries generally need to be set the PreDefault LoadingPhase so they can be properly loaded before game-specific data that loads early in the Default load ...
UV Flipping Mode Causes Stretching of Particles
UE - Niagara - Nov 17, 2017If "UVFlipping Mode" under Rendering on the Required node of an emitter is set to anything other than "None," the particles can become stretched and distorted. As a workaround, I have discovered th ...
Crash When Assigning a Static Mesh to the "Sample Static Mesh" Module
UE - Niagara - Jun 28, 2018When assigning a static mesh to the "Sample Static Mesh" module, the engine will crash as soon as you select a mesh and click "Fix Now". If the mesh already has CPU access enabled it will crash as s ...
Edits of node properties that are not stored on pins do not diff correctly
UE - Gameplay - Blueprint Editor - Oct 2, 2015Currently details changes to the following are not noticed by the Diff tool when diffing AnimBPs:State Machines (i.e. Max transitions per frame)Transition rulesConduitsStates This also affects non- ...
Crash on startup with a Blueprint deriving from an abstract class with a SpriteComponent
Tools - Feb 7, 2018Appears to be an issue with load order and the timing of when we populate the 'ShowSpriteCommands' and 'SpriteIDToIndexMap' containers, which we assert on if they're not the same size. The original ...