Unreal Engine Issues
Unreal Engine Issues
Crash when switching from Lumen visualization to raytracing visualization
UE - Rendering - Graphics Features - Mar 27, 2026When switching from Lumen visualization to raytracing visualization via the console, the editor can crash to desktop. The crash appears to happen deep within the driver libraries, and does not trig ...
Changing MaterialQualityLevel causes a crash due to a ShaderMap mismatch in UniformExpressionCache
UE - Rendering - Architecture - Materials - Nov 26, 2025A crash may occur when changing the MaterialQualitylevel via Scalability due to a race condition. The issue occurs because in ScalabilityCVarsSinkCallback(), when it creates the FGlobalComponentRec ...
Crash Occurs When Attempting to Resume Execution After Hitting a Breakpoint in a BT Task
UE - Gameplay - Oct 6, 2017When a breakpoint is hit in a BT Task, if you attempt to use CTRL+P to search for and open the BT the task is being run in, try to resume execution, and then return to the original BT Task Blueprint ...
Linux: Assertion at splash screen when trying to open UE4Editor
UE - Platform - Linux - Mar 21, 2017I ran into this while looking to verify [Link Removed] at CL 3355923. I logged the issue I was verifying the fix for last night and have not updated anything locally, so the "OpenGL 4.3 not supporte ...
New VR-Basic level triggers Metal validation layer assertion
UE - Platform - Apple - Mar 16, 2020This was discovered externally and reported on UDN here: https://udn.unrealengine.com/questions/563268/mac-editor-crash-when-disable-ambient-occlusion.html ...
A Skeletal Mesh simulating physics that hits a Geometry Collection Actor with OneWayInteraction true, OneWayInteractionLevel 1, and is using Damage Propagation (default) will be accelerated so fast it immediately disappears by hitting the world limits
UE - Simulation - Core - Jan 20, 2025A Skeletal Mesh simulating physics that hits a Geometry Collection Actor with OneWayInteraction true, OneWayInteractionLevel 1, and is using Damage Propagation (default) will be accelerated so fast ...
Crash when force deleting Dataflow Graph
UE - Editor - Workflow Systems - Jul 31, 2023When force deleting a dataflow graph with the dataflow graph editor open it will crash the engine. This issue is occurring in Binary //UE5/Release-5.3 @ CL 26560699 This issue is occurring in Binar ...
Slow-rendering thumbnails can be queued up for real-time updates
UE - Editor - Content Pipeline - Content Browser - Sep 22, 2016A licensee is seeing performance drops while using the editor due to a custom thumbnail renderer taking a while to generate thumbnails while Real-Time Thumbnail rendering is enabled, and has request ...
Debug lines can be obscured by post processing effects
UE - Graphics Features - Sep 14, 2015Debug lines (Results of DrawDebugLine()) can be obscured by post processing effects such as a strong glare. Debug lines should be always visible for debugging purposes. ...
SunTemple is washed out in one color on some Android devices.
UE - Platform - Mobile - Jan 16, 2017This was discovered during the 4.15 mobile compat. ...