5.8.4 Hotfix Released

General Announcements
, ,
1

5.8.4 has dropped with lots of fixes and updates!

Please feel free to share feedback and discuss the current version in the release topic, Unreal Engine 5.8 Released.

If you experience a bug with the 5.8.3 Hotfix, please follow the How to Report a Bug guide to report it on the Bug Submission Form

  • Editor
    • Editor (Bug Fix)
      • Fixed an issue where the editor opened a new instance of Visual Studio 2026 each time it opened a source file, such as when you click a Blueprint’s C++ parent class link, instead of reusing the one already running. The editor now recognizes the new .slnx solution format that Visual Studio 2026 uses. This also fixes the Open Solution toolbar button, and saving your open Visual Studio documents before a Hot Reload compile. When both a .slnx and a .sln solution exist, the editor now opens the .slnx, because that is the format Visual Studio 2026 works with. If the .sln is the only one present, the editor still uses it.
      • Fixed a crash that could happen when closing the editor while the sequencer tab was open.
    • Framework (Bug Fix)
      • Gizmos Fixed the four-arrow move cursor sticking in tool viewports after a Shift marquee selection.
    • Interchange (Bug Fix)
      • Handle more primvar baking datatypes and fix a few primvar baking issues when importing via Interchange USD scenes with geometry caches and skinned or collapsed meshes.
    • Scripting (Bug Fix)
      • [MHA] Don’t crash Mac/Linux editor on scripted Live Link Face ingest
  • Foundation
    • Build (New)
      • UnrealBuildTool: Allow PVS Studio to work with different preprocessors.
    • Build (Bug Fix)
      • Fixed a stall in UAT log output that buffered 1024 lines
    • Dev Tools (Bug Fix)
      • Fixed a bug that resulted in garbled output from the commandlets when running UAT on a system that is set to a non-latin codepage (Japanese, Chinese…)
      • Fix a bug that broke timestamp check on libraries when compiling\linking.
    • Horde (Bug Fix)
      • Horde: Prevent path traversal when extracting artifact and workspace contents
  • Framework
    • Blueprint (Bug Fix)
      • Fixed crash when adding a function call node via an editor script
    • Gameplay (Bug Fix)
      • Mover: prevent several concurrency-related crashes involving trajectory prediction from a worker thread
  • Level Design and Art Tools
    • Geometry Core (Bug Fix)
      • A crash (“Array index out of bounds: 0 into an array of size 0” in ComputeMikktTangents) when building a static mesh that has no UV channels with MikkTSpace tangents enabled.
    • Landscape (Bug Fix)
      • Fixed assert in water zone when toggling persistent level visibility
      • Fixed semi-random crash when loading an old landscape (one without edit layers)
      • Fixed rare crash in landscape following an undo.
      • Landscape - Fixed assert when auto-filling target layer assets in an unsaved level, if the last browsed level in EditorPerProjectUserSettings.ini is rooted.
    • Modeling Tools (Bug Fix)
      • [Modeling] MeshSelectionTool: Fix crash when action hotkey pressed during brush stroke
      • [ITF] Fix editor crash when a transform gizmo is given an unsupported coordinate system - demote checks in UCombinedTransformGizmo::Tick and UIntervalGizmo::Tick to ensures that fall back to Local, so unsupported values don’t crash the editor
  • Media
    • Media (Bug Fix)
      • Improved validation of TMV transcode job lists imported from JSON.
      • Fixed a crash when playing very high-resolution tiled TMV files (larger than 8K, such as 16K) through ImgMedia.
      • Fixed a D3D12 crash when playing NDI sources with the NDI Media plugin.
  • MetaHuman
    • MetaHuman (Bug Fix)
      • Fix RigLogic twist angle extraction affecting half rotation computations on fingers
      • Fix crash if RigLogic DNAIndexMapping gets out of sync with the current DNA being evaluated
  • Motion Design
    • Motion Design (Bug Fix)
      • Fix crash when switching to camera view mode and trying to move the camera.
  • Movie Render Pipeline
    • Movie Render Pipeline (Bug Fix)
      • Fixed a garbage collection issue in viewport hit proxies that could cause crashes when rendering out Object ID passes.
      • Fixed a crash that could occur when rendering a sequence without audio (or some shots exclude audio), and audio is a requested output from the graph.
  • Online
    • Online (New)
      • EOSSDK v1.19.2.1 update, binaries only.
  • Platform
    • All Apple (Bug Fix)
      • Preventing Apple Platform Web Browser from attempting to create a screenshot texture on a view with 0 pixels
    • Mac (Bug Fix)
      • AutomationTool - CreatePaksUsingChunkManifests - Updated Lookup path so that it works for Mac platforms and not just Windows particularly for projects that live outside the UE root.
  • Platform Mobile
    • iOS, tvOS, and iPadOS (New)
      • Update iOS client to use UIScene lifecycle by default
      • Add iPhone17e, new iPhone18Pros and new iPadAir devices to the base profile
    • iOS, tvOS, and iPadOS (Bug Fix)
      • Fix iOS .app finalize failing with “Bad file descriptor” with macOS27
  • Rendering
    • Rendering (Bug Fix)
      • Fix array out-of-bounds assertion failures in Static Mesh build during UV density accumulation.
    • Architecture (New)
      • Fix assert in MaterialShader ShaderMapId.ContainsShaderType caused by mismatching conservative and compilation shader parameters. The root cause of the assert is the fact that programmatic modifications of Usage Flags were not updating the CachedExpressionData, leading to stale data at shader compile time. The fix is to update the CachedExpressionData each time a programmatic SetMaterialUsage happens, similar to the manual editing path where it happens on PostEdit.
    • Lumen (Bug Fix)
      • Fixed a regression in Lumen indirect lighting where the atlas is mistakenly cleared every frame when a SceneCapture2D is rendering
    • Materials and Shaders (Bug Fix)
      • Fix undo on material root node pins
      • Fix a cancellation race condition for shader compile jobs which fail preprocessing
      • Fixed a bug in the shader preprocessor when encountering unclosed string/char literals - previously would scan past the end of the file (and likely crash). Now reported correctly.
    • Niagara (Bug Fix)
      • Fix for audio sampling DI assert if things are shutdown before enough samples has been collected to fully initialize things.
    • Path Tracer (Bug Fix)
      • Path Tracer: Fix missing specular profile in certain substrate materials
    • RHI (Bug Fix)
      • Improved the implementation of enhanced barriers on D3D12 for compliance/correctness.
    • ASD (New)
  • Simulation
    • Simulation (Bug Fix)
      • [ChaosVehicles] Fix vehicles not receiving input when Physics Prediction is enabled and the vehicle is driven by an AIController.
  • Virtual Production
    • Compositing (Bug Fix)
      • Composure: Fix material output override validation crash when using post-process material passes.
2 Likes
2

Known Issue:

UE–401568 - [PCG Editor Mode] Paint Tool fails to be updated in real time

Workaround:

Performing any other action will cause the meshes to appear.