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.
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)
Support for generating SODBs via the ASDTool for compute shader and bundled PSOs from a cooked game
Developer workflow ASD testing tools for local compilation and registration
Thank you! It’s been almost 5 months and no one has said anything about this and it’s a big problem! Is this going to be fixed?? Thank you! (see my bug report below)
Why hasn’t the serious incompatibility bug between the two ray tracing functions in the semi-transparent mode and the Niagara particle effect and materials with masked textures been resolved yet…?
In UE5, the Niagara particle effect suffers from a long-standing and severe incompatibility bug with PostProcessVolume: enabling Translucency (ray tracing mode) causes the Niagara particle effect to malfunction and become undetectable. When will this major bug be fixed…?
I’ve already tested the Substrate version (5.6-5.8). As soon as I enable two ray tracing settings in semi-transparent mode, the Niagara effect immediately becomes bugged and malfunctions, disappearing completely…
—Selecting the semi-transparent mode: One out of two ray tracing options is selected; however, many semi-transparent materials with masks or overlays also experience a major bug where they disappear completely
was successfully working in 5.8.2 and when I updated to 5.8.4 I get the following error message : Plugin ‘Mutable’ failed to load because module ‘MutableValidation’ could not be loaded. There may be an operating system error or the module may not be properly set up.
Unreal then crashes, so I cannot work or load any of my earlier work or projects.
