Unreal Engine Issues
Unreal Engine Issues
[CrashReport] UE4Editor_CoreUObject!FScriptArrayHelper::EmptyAndAddUninitializedValues() [unrealtype.h:2703]
UE - Gameplay - Blueprint Compiler - Aug 15, 2017This is a trending crash coming out of the 4.17.0 release. Based on user descriptions, this crash occurs on Play or Compile for affected users. User DescriptionsAgain crashing when I hit playIF I C ...
FStateTreeRunParallelStateTreeTask and TStateTreePropertyRef
UE - AI - StateTree - Dec 2, 2025When using a state tree that has a StateTreePropertyRef as a parameter in parallel any references will fail to resolve using the GetPropertyRef node. ...
[CrashReport] Mac crash - TArray<FDeferredMacEvent, FDefaultAllocator>::ResizeGrow
UE - Platform - Apple - Sep 14, 2017This is a somewhat common crash on Mac that has affected users since 4.16. Users have not provided any descriptions of their actions when the crash occurred. Callstack from Log [2017.09.08-05.17. ...
Get Mouse Position Blueprint node returns different values outside of viewport depending on whether it was called from Event Tick, or within an Actor function
UE - Gameplay - Nov 15, 2018There seems to be a discrepancy between the output of Get Mouse Position node depending on whether the node is inside an Actor function or called from Event Tick. If the node is present inside a fun ...
Wrong WPO motion vectors due to Periodic World Space node
UE - Rendering - Graphics Features - May 13, 2026We've noticed smearing in grass due to wrong motion vectors. This appears to be caused by lack of previous frame support in the periodic world space node. This is how we fixed it: In MaterialTempl ...
Crash when casting to owner from AnimGraph
OLD - Anim - Sep 6, 2016Crash occurs when casting back to the pawn owner from the Anim Graph. In this case, it is being used for "Copy Pose from Mesh" Workaround: Cast to Owner from Event Graph, defining variable as the ...
[CrashReport] Crash on Mac related to editor close
UE - Platform - Apple - Jun 6, 2017This is a long-standing Mac crash that occurs with low frequency, but has affected more than 500 users since it started (possibly in the 4.11 release) It has recently been experienced internally by ...
Changing blueprint default values inside arrays only updates loaded child blueprints
UE - CoreTech - Jul 30, 2020The rules for delta serialization in UE4 are complicated, and the editor tries to hide them from you, which works 90% of the time but can lead to confusion and data loss in other situations. In the ...
Nanite: unused VertexInterpolator node disables Opacity Mask (material renders opaque)
UE - Rendering - Architecture - Jun 8, 2026On Nanite meshes, placing a VertexInterpolator node in a material graph without using it (unconnected, or routed through a disabled static switch) silently breaks the Opacity Mask and the material r ...
Fractured Geometry Collection triggers a crash when colliding with an Animation Blueprint with a Rigidbody Node
UE - Simulation - Core - Sep 25, 2023This is not a regression. Tested in //UE5/Release-5.2 CL26001984 The editor crashes when a physics asset of an animation with rigid body collides with geometry collection. ...