Unreal Engine Issues

[CrashReport] UE4Editor_ClassViewer!TBaseMulticastDelegate<void>::RemoveDelegateInstance() [delegatesignatureimpl.inl:970]

This is a common crash affecting users on Windows and Linux. It also appears related to an older Mac crash ([Link Removed]). Users have not provided any new descriptions. Source Context 959 ...

[CrashReport] UE4Editor_CoreUObject!FMemoryWriter::Serialize() [memorywriter.h:42]

This is a common cook crash affecting users in 4.16. It is possibly the same issue as described in [Link Removed] for past engine versions. Source Context 33 virtual void Serialize(void* ...

Hitting S while Alt + Dragging a BSP and then Stopping PIE will crash the editor

Hitting S while Alt + Dragging a BSP and then Stopping PIE will crash the editor. Reproduced in 4.7.1 binary and Main (//depot/UE4/Promotable-CL-2455917) Crash Report: [Link Removed] Call Stack:< ...

Gradual drop in Performance on Windows 10 projects after Toggling Fullscreen

It seems that when working in any project on a Windows 10 machine, there is a gradual rise in frames per second and a consistent drop in performance. The user reporting this issue claims his frame ...

Data loss caused by C++ Child Actor Component when compiling Child BP

Having Child Actor Components that are set in code can cause data loss upon compiling the blueprint. In this particular scenario, there are two custom Actor classes involved, MainActor and SubActo ...

Null Material Layers in Material Instances cause Opacity Mask and WPO to break on Nanite Meshes

When a Material Instance is loaded that has a nullptr layer in StaticParametrs.Materiallayers.  The Material Instance will create it's own CachedExpressionData but the ConnectedParameterMask will be ...

Duplicated TextureLoadVirtualPageTable in GetCustomData functions in generated HLSL add to the total instruction count due to TextureLoad having side effects

When using materials with CustomData inputs, such as the Eye material with Iris Distance and Mask, Virtual Texture samples will increase the instruction count for each unique VTPageResult. Each cus ...

Staging Directory in Project Packaging Settings should not be saved as absolute path

When you package a project via the editor, it updates the ProjectPackagingSettings to set the StagingDirectory to the specific one chosen by the user. However, it saves this path as an absolute path ...

WP HLOD Crash on Small Cell Sizes

Clicking the GameMode Override dropdown in the World Settings tab crashes the editor

Clicking the GameMode Override dropdown in the World Settings tab crashes the editor. Also occurs with any of the sub-options for the GameMode. Does not appear to occur if there is not already an ex ...