Unreal Engine Issues
Unreal Engine Issues
Certain Projects crashes on Start AR on iOS
UE - Platform - XR - Jun 11, 2025Repro rate 5/5 Project crashes on pressing "Start AR" in ARDebugCheck, on "Begin Scan" in Handheld AR Template and on "Start AR" in ARImageDetection. Issue also occurs on ARVideoSettings and ARSave ...
Enum with "MAX" element at other than the last element removes user defined last element
UE - Foundation - Core - Oct 18, 2019FNativeClassHeaderGenerator::ExportEnum produces this behavior. If an enum has “MAX” somewhere in the array, it removes last element. I tested my code to fix the issue.// code placeholder bool UE ...
Clothing Data Cannot Be Created If The Old Data Was Deleted While Applied
UE - Simulation - Physics - Character - Jan 16, 2020When you delete clothing data on a skeletal mesh before removing it you cannot apply new clothing data. The engine still thinks that there is clothing data is applied. I tested using the Paragon: Tw ...
Alembic Geometry Cache is corrupted on reopening of project leading to crash
UE - Foundation - Core - Dec 20, 2016Alembic Geometry Cache crash when re-opening the project and a map that contains this asset or adding it to any existing/new levels will instantly crash the editor. This asset works correctly in the ...
Window to select Skeletal Mesh does not pop up when editing a new IK asset
UE - Anim - Rigging - Retargeting - Apr 26, 2023When opening a new IK rig, the window that prompts the user to select a skeletal mesh does not open immediately. However, a skeletal mesh can still be selected in the details panel in the IK window. ...
Incorrect Lumen Scene direct lighting when objects behind masked landscape
UE - Rendering - Graphics Features - Lumen - Oct 5, 2025When objects are placed behind or beneath a masked landscape and r.Lumen.HardwareRayTracing.SurfaceCacheAlphaMasking is enabled, the direct light evaluation is incorrect. There are two workarounds, ...
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UE - Editor - Feb 5, 2026The cursor position is no longer updated during drag and drop, so drag-over events cannot respond correctly.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 ...
A crash happens with a combination of Event Receive Tick AI and a pawn losing possession
UE - AI - May 18, 2022User reports this is a regression because it worked in 4.27, but they converted to 5.0.1 and now it causes a crash. However, I'm unable to verify this at this time. A crash happens with a combinati ...
MetalRHI Asserts When Using "Profile GPU" With RHI-Thread/Parallel-Execution
UE - Graphics Features - Sep 14, 2016When the RHI thread is enabled (with or without parallel-execution) for Metal it isn't currently possible to run "profilegpu" because the GPU timestamp emulation code isn't multi-thread safe and pro ...
ExpandEnumAsExecs always uses first Exec if an argument name matches Enum value
UE - Gameplay - Blueprint - Jan 13, 2023Reproduced 3/3 times, issue also occurs in //UE5/Release-5.0 - CL 20979098 Binary. Confirmed NOT a Regression. EnumBugBP uses two enum cases and three argument cases for 6 total permutations:Enum w ...